for me it has come down to limited outside storage, so we don't have a ton of outdoor games, however our most-used is one of these quick-setup badminton sets. We always have onhand couple frisbees, some type of playground ball, football.

Minnow nets so the kids can try to catch creatures anytime we are near a lake/creek/river. Also if you have kids, I highly recommend this aquarium bucket thing - super fun for them to observe creatures they catch.