Swing Glitch: This might be the most popular fun glitch. You get a car and park it in the middle bar of the swing set in Broker and wait for like 20 seconds max and it willl send your car fucking flying. The car will get smashed the fuck up pretty good though.
Airport Glitch: Go to one of those slope ramp things at the main airport building and run to the top and jump, you should be closer to the top... immediately jump again before you slide back down and you'll hop over the wall and be inside the airport... you'll be able to shoot out and nothing can get in.
Bow-hahn Glitch: I don't know too much about this except that it is just a way to take advantage of something that isn't solid. Similar to the airport glitch. I don't know the exact location but I do know that it's on a beach and you jump on a ledge but jump extremely close to the wall and immediately start shimmering to the left and you should be able to go through the wall... there's nothing but water and empty space besides the end of the ground there though.
Crate Glitch: I don't know what the fuck was going on Duffman and them were doing this shit. You open the doors to some random crate in Algonquin and run a car into it and the crate goes fucking insane and tears up the shit around it like a fucking tornado or something. Someone will have to provide some info on this.
Bike Glitch: I don't know what this is but some niggas were doing this in free mode today... they said something about bikes hovering or some shit. You shoot out the back tire, have someone get on the motorcycle and drive in a circular motion. Sounds like bullshit to me because it didn't work when they tried it.
Feel free to submit your own glitches.