I have become addicted to just walking around and fucking with the dudes that won't leave the chick characters alone. It's a pedo bear wet dream on that shit.
I also like settin' up shop with a bubble machine, crouching near it, and making it look like I'm dumping in it and bubbles are coming out. Besides the tons of mini games that are available, most of the fun is just seeing the reactions of other people when you do something stupid in front of them.
Smokin a blunt and fucking with people has made me crack up on more than one occasion.