I've had 4, FOUR, separate hits tonight of people who googled the words "what to do on a friday night". I figure it's my duty to help these poor, bored souls out... These have all been tried and tested by ME!
*Take a friend and stuff them into the trunk of your car. Do it in a highly conspicuous area, and make sure their hands/feet are hog-tied, and there's sufficient duct tape on their mouth. Make sure other people see your struggle. Drive away laughing your guts out and yelling "You better shut it back there!!"
*Take rolls and rolls of butcher paper up to your local mountain/hill and use it to spell the initial of your preferred college. Anchor it down with rocks or else it'll blow away.
*Dumpster Diving. 'Nuff said.
*Skinny dipping, hiking, or possibly streaking, though make sure you don't get arrested.
*Billboard dancing. Climb up on the billboard of your choice and dance away. This might possibly get you arrested too, so be careful.
*Drive to somewhere with legalized gambling. Here in UT we'd go to Wendover, NV or Mesquite, NV. Don't take any money. Hit on the hottest guy you've ever known, and spend the night in his hotel room with him. Remember his name and his Armani suit 10+ years later. *sigh*
*Hop fences into peoples back yards and use their hot tubs. Although, now as a homeowner with a hot tub, I'd kick your ass if you hopped my fence. So beware and be quiet.
*Sneak into movies.
*Get hypnotized on stage by a comedian. Make ass of self.
*Karaoke. Any time, anywhere, anybody. Ah, sweet karaoke. My friend.
Ok well if you haven't figured out something to do by now, I don't think I can help you much. Take special note here: none of these things involve alcohol, and most of them will get you into trouble. Be well...go forth...