At a pool on Starfish Island you can find a beach ball. If you run into it it will bounce up into the air. Stand in the ball's shadow as it falls and it will bounce on your head. A number will show up above your head for each time you've bounced it. When your look at your stats in the start menu it will show: " Highest score on Beach ball mini-game ".
It works for both games. First find a car with somebody driving it. Stand next to the driver's side (it doesn't work on the passenger's side) and enter the "destroy all cars" code. When you reach the Y button in the process of entering the code your character will pull the driver out of the vehicle. Finish the code before your done pulling the driver out and the car will explode but you will get inside anyway. Hurry up and enter the health code because the car will be in falmes. Now you're driving a blown-up car. You can take it to a pay-and-spray and the car will be repaired but will keep it's charred look.
When chasing down a car in a vigilante mission, pause the game when the are in your sights. The criminal willl get out of the car, making them an easy target to run over.
Begin by going to Salvadore in Portland, and start the "Bomb Da Base" mission. Once you arrive at 8Ball's place and collect the money for him, take the Sniper Rifle from him. While still having him standing in his doorway, zoom in on his head and shoot it. The next time you start the mission 8Ball's body will be invisible, and his head will be floating and talking to you.
The weapons can be found at the 3 major hideouts. The Sea Sparrow can be found behind the Diaz Mansion. The Rhino and Hunter can be found at the air force base.