Bring back the scavenger hunt you did for your kids when they were younger, but blow it out and make the boundaries bigger — this is great for teens used to getting themselves places on their own. Divide the guests into teams, and start the party with the teams decorating T-shirts — make sure to have a robust supply of fabric markers and sharpies. Hand out lists of clues, have the kids use their smartphones to snap the items on the list, and meet up after an hour or so. Don't limit the clues to simply finding places or historical markers; include some silly acts that teenagers secretly love to do, like singing a hit song from their early years or doing cartwheels in the park. This is great for a coed party, too.
