When you take Lenny out to the desert to decide whether to kill him or spare him, there is a secret and hilarious way to kill him if that is what you choose. Don't kill him. First, look around, and you'll see 5 vultures, some in air, with some perched. Make sure all of them are in air by running up to them and scaring them away. Then shoot all 5 down with any gun, and just wait. All of a sudden, an ice cream truck comes out of nowhere and runs over Lenny, sending him sky high. Interestingly enough, the ice cream truck seems very similar to that of the one in the Prologue.