(If there's a tips & tricks section here, feel free to move this! This didn't really fall under 'Gameplay')
For many years I've had this recurring dream of planes falling out of the sky, huge commercial airliners, crashing just far enough away from me that it doesn't kill me. And after messing around a little, I actually lived it! In GTA Land, anyway.
The outcome: Watch a 747 (for more awe-inspiring results) come straight at your character, and crash really close to you (or ON you, if your aim is good!)
Steps to reproduce: I put Michael up in a 747 (can be easily grabbed from the airport once your character has purchased a hangar there), and put him up in the air over Los Santos. Then switched to Franklin, who was, during the 12 or so times I tried this, either at the beach doing pullups, or at home in the hills washing his car. While Michael's plane is sorta hanging in a suspended state, I had Franky get on his bike and rude up to the Vinewood sign (anywhere open is fine). I took the 'spine' of the hills and ended up under the 'N' of the sign. Have Franklin get out of his car, and aim his view south, toward the city. Switch back to Michael, who apparently hasnt moved in all that time, and make a bee-line for the 'N' of the Vinewood sign.
When you get close enough, you can switch back to Franklin. But thing is, Michael's plane has to be REALLY close to Franklin for this to work. If Mike's still too far away, you'll see the big 747 flash for a split second. (Unless you're still REALLY far away). Yeah, point is, Mikey's plane has to be maybe 100 feet away before you switch to Frank. That'll be just enough time to either see the plane crash in front of you, ON you, or fly right over your head and crash behind you.
Aiming that huge sucker's a bit tricky, because you'll need to adjust the plane's altitude each time ya switch to it....like in my case, I needed to aim the plane down to the ground. But every time I switched back to the plane, it was leveled again. So standing on the side of a hill helped a lot, since I could fly the plane into the dirt without nosing down.
Anyway, I thought this was kinda neat, so figured I'd share. I've been having fun trying to find different ways to make the protags interact (in ways they werent meant to) Also, the plane and the characters you use are optional.