Color wars ethier between dorms or floors. Games like beer pong (no booze), foot races, dizzy bat.... Winner gets a full taco or pizza party or something. Seems lame I know but I am guessing the dorm you live in is Freshman or people underage, so you can't really serve booze.
My freshman year we had bed races, so all the dorms came up with a theme; dressed as that theme, and made a bed on wheels. They raced them down a road side by side, 4 people pushing and a couple people on the bed. I wasnt involved but it was very fun to watch.
Also you could see if other dorms what to throw their money in and get a bouncey house and have fair games in the court yard. GOOD LUCK MAN