Unreal Tournament III

The "Bullseye" award is earned for killing an enemy with a vehicle self destruct.

Suggested Setup
Gametype: Vehicle CTF
Map: Sandstorm
Mutators: Speed Freak, Weapon Replacement (If playing against bots, all to Impact Hammer)

Same sort of idea as Ace, play in split screen and have your second player stand beside the outside corner wall of the small square building that the enemy flag is in. Now with your player hop on the Viper that is to the back of your base behind your flag. Zip over to the enemy base then line up with your second player. Hold :L1: to jump up in the air, then release it when aiming at your second player to launch the Viper at them, which will self destruct and kill them on impact. As long as it says they were killed by "Viper Self Destruct" then you are good. Return to main menu and repeat until you earn the trophy.

The same setup is used if you want to play against bots. Have Weapon Replacement set so all weapons are Impact Hammer (so that no on is shooting at you). When the match starts run and grab your Viper then head over to the enemy base. This will be slightly harder because you need to hit a moving target with the Viper, but it works the same. After you kill an enemy with the Self Destruct return to main menu and repeat.