Whether you're trying to entertain restless kids or looking for a cheap way to have fun with a group of friends, planning an outdoor scavenger hunt is the way to go. Head to a nearby park and hide clues or compile a list of specific items that your participants have to find. Not only is this an excellent social activity, you can sneak in some exercise by offering a reward to the team who finds everything in the shortest amount of time (that'll get them running!) Then finish off the day with a healthy potluck picnic.