Here's what I've been able to find, so far (If anyone has seen other reports that include timestamps for the events that night--either ones that confirm these, or ones that contradict them--please let me know so I can add them to this post.):
During the All-Star Game, February 26th - Trayvon Martin leaves his father's girlfriend's house during the All-Star Game on February 26th, to go to 7/11. - (Trayvon Martin shooting timeline leaves many unanswered questions)
After he left the store - "[Trayvon Martin] was on the phone with his girlfriend back home in Miami after he left the store. Martin told the girl he'd taken shelter from the rain briefly at an apartment building in the gated community before continuing his walk to where he was staying with his father nearby." - (Trayvon Martin's final phone call: 'He said this man was watching him')
The last call was at 7:12 p.m. (I'm guessing that's a start time, and "just after he left the store," as above.) - "Martin, who was in town from Miami to visit his father in Sanford, called his 16-year-old girlfriend in Miami several times on Feb. 26, including just before the shooting, Crump said. ...
The teenager told the girl on his way back from the store he'd taken shelter the rain briefly at an apartment building in his father's gated community, Crump said. Martin then told the girl he was being followed and would try to lose the person, Crump said.
"She says: 'Run.' He says, 'I'm not going to run, I'm just going to walk fast,'" Crump said, quoting the girl.
After Martin encountered Zimmerman, the girl thought she heard a scuffle "because his voice changes like something interrupted his speech," Crump said. The phone call ended before the girl heard gunshots.
The last call was at 7:12 p.m. Police arrived at 7:17 p.m. to find Martin lying face down on the ground." - (Fla. Teen on Phone with Girlfriend Before Shooting)
7:11 PM - (was "Shortly before 7:15 PM"?, pre update.) (I'm guessing closer to 7:10 pm - See below) ***UPDATE*** (with thanks to "Hoofbite" in comments) The Sanford police reports that Zimmerman's call was received at 7:09 PM, he was connected to a dispatcher at 7:11 PM, and that he spoke to the dispacher until 7:13 PM, at least /UPDATE - ""Shortly before 7:15 PM, George Zimmerman spots Trayvon standing outside the development's clubhouse near the community mailboxes, where the teen had ducked under an awning to get out of the rain. Zimmerman calls police on a non-emergency number from his SUV, saying he sees a suspicious person.
When Trayvon leaves the clubhouse, Zimmerman pursues him in his car." - (Trayvon Martin shooting timeline leaves many unanswered questions)
??? (but during Zimmerman's 4 minute phone call with police dispatcher (at this YouTube video, 1:26-5:31) - "Trayvon goes off the road to walk between two rows of town homes, down the lane from his destination, Zimmerman gets out of his car and pursues him on foot. He tells the dispatcher "oh shit, he's running." the dispatcher asks if he is pursuing the subject. When Zimmerman says he is, the dispatcher says, 'we don't need you to do that.'" - (Trayvon Martin shooting timeline leaves many unanswered questions)
??? - "It was then that Martin told the girl he was being followed, according to Crump. She said Martin told her someone was following him and that he was going to try to lose him. He thought he had lost Zimmerman but hadn't.
"He says, 'Oh he's right behind me, he's right behind me again,'" Crump says the girl told him. "She says: 'Run.' He says, 'I'm not going to run I'm just going to walk fast.' She hears Trayvon say, 'Why are you following me?' Other voice says, 'What are you doing around here?'"
She told Crump they both repeated themselves and then she thinks she heard Zimmerman push Martin "because his voice changes like something interrupted his speech." She heard an altercation and then the phone call was cut off.
Within moments, according to Crump's timeline, Martin was shot. She didn't hear the gunfire." - (Trayvon Martin's final phone call: 'He said this man was watching him')
"They don't get far. Just around the back lane, Trayvon is confronted by the stranger in a red jacket and jeans - he's not dressed like a police officer.
Trayvon's girlfriend is still on the phone. She says she hears someone confront Trayvon, and ask him what he was doing there. The phone drops.
At that time, the first 911 call is placed to police by an alarmed neighbor, who reports hearing a fight going on in their backyard. It was followed in rapid succession by five more calls to the emergency number. One caller says she hears someone screaming for help, and then gunshots.
7:17 p.m. - At 7:17 p.m., the first officer, Officer Smith, arrives at the gated complex, responding to Zimmerman's 911 call. In his report, he says that as he arrives, dispatchers notified him of the 911 calls reporting shots fired in the area." - (Trayvon Martin shooting timeline leaves many unanswered questions)
As far as I can find, the time codes for the 911 calls have not been released. (This info is crucial, especially since one of them can pinpoint the exact moment the gun went off.)
Similarly, the info saying exactly what time the call between Trayvon Martin and his girlfriend terminated--pinpointing exactly when the physical altercation began--(available on his missing(?) cellphone, his girlfriend's phone, and his cell carrier) also has not been released.
Even so, this timeline indicates only three or four minutes elapsed between Zimmerman's call to the dispatcher "shortly before 7:15 PM" and the first officer's arrival "at 7:17 p.m.," AFTER the following on foot, the verbal and physical confrontation between Martin and Zimmerman, and the fatal shot.
(Something HAS to be wrong with this info, however, since Zimmerman's call with the police dispatcher lasted four minutes, five seconds all by itself, according to this YouTube video. It's likely that George Zimmerman's call to the police was initiated several minutes earlier, perhaps closer to 7:10 pm, if not earlier, and ENDED shortly before 7:15 pm.
The call between Trayvon Martin and the girl in Miami--and especially her "ear-witness" testimony, saying that it sounded like Trayvon was pushed or hit--calls into question Zimmerman's allegation that he had his back to Trayvon Martin and was walking back to his truck when Trayvon "attacked" him from behind. (Admittedly, both Zimmerman's and Trayvon's girlfriend's statements may well be biased, given who they are.) And, not to get too conspiratorial, but it's kinda odd that Trayvon's cell phone and earpiece were not recovered at the crime scene, and are not in police or Martin family custody.
I also wonder about the physical evidence.
What do they know about where Trayvon and Zimmerman were when the latter fired the fatal shot?
Was Zimmerman laying on his back with Trayvon over him, perhaps punching him, or were both men standing, facing each other?
Based on where on his body he was shot and how he fell (face down), along with any blood, gun residue or other evidence on Zimmerman, what does that suggest?
What produced the cut on the back of Zimmerman's head, and are there scrapes or bruises on Trayvon's hands or feet (or anywhere else) that correspond with Zimmerman's injuries, indicating where either/each man was when the injuries took place?
***ANSWER***, at least according to the Sanford police, citing George Zimmerman's version of events. (Police were unable to obtain a statement from the only other witness to these initial events, Trayvon Martin. I suspect that his side of the story would likely differ from Mr. Zimmerman's, however, were he available to tell it.):
"Zimmerman told them he lost sight of Trayvon and was walking back to his SUV when Trayvon approached him from the left rear, and they exchanged words.
Trayvon asked Zimmerman if he had a problem. Zimmerman said no and reached for his cell phone, he told police. Trayvon then said, "Well, you do now" or something similar and punched Zimmerman in the nose, according to the account he gave police.
Zimmerman fell to the ground and Trayvon got on top of him and began slamming his head into the sidewalk, he told police." - (Trayvon Martin: George Zimmerman's account to police of the Trayvon Martin shooting. - Orlando Sentinel)
Where were the iced tea can and the package of Skittles found?
Did Trayvon hit Zimmerman with either item?
Were they dropped several feet away, indicating that a) the struggle started here, or b) this is where Trayvon dropped them before running up on Zimmerman?
Did Zimmerman have any other tools with him (for instance, the flashlight that several of the 911 callers reported seeing after the shot, unclear whether it belonged to one of the "fighters" or a responding officer)?
I'll add answers, more questions, and otherwise update and correct this post as more info becomes available (or the mood strikes me.)
Fla. Teen on Phone with Girlfriend Before Shooting
Trayvon Martin's final phone call: 'He said this man was watching him'
Trayvon Martin shooting timeline leaves many unanswered questions (Be sure to read page two, which discusses what the police did--and didn't--find on the scene that night.)
Trayvon Martin, The 911 Calls - High Quality 911 Audio - Including George Zimmerman - YouTube (Zimmerman's call: 1:26-5:31)