Traditional board games are a huge hit at 13th birthday, especially if they are paired with a more grown up activity later, such as makeovers or paint ball. Bring out Twister, Mouse Trap, Monopoly and Checkers, and give a prize to the winning team — whether it's first dibs at pizza or a small toy. For more rambunctious party guests, play Freeze Tag, Red Rover or Hide and Seek.
Other games include scavenger hunts, which are great fun for preteens and teens. Create a mall scavenger hunt tailored to the guests. Make a girls- or boys-only version and play against each other, or create a hunt everyone can participate in together. For an at-home scavenger hunt, send the boys into the woods for things out of nature, and let the girls ramble through closets to find accessories and shoes.
Water gun fights are always fun for boys, and many girls love them too. Just remind guests to bring a change of clothes. Make teams of those over 13 and those under 13, or play boys against girls. Parents and chaperones versus kids makes a great surprise game — ambush the partygoers, and then hand over some water guns for their revenge.