As the name suggests, this game is just like golf, but with frisbees for balls and baskets for holes.
Get hold of as many baskets (eg Laundry Baskets) as you can, and stick numbers on them to indicate the hole number. You may need to weigh the baskets down with something heavy if it's windy.
Design the holes so there's different variations - longer or shorter holes, some with obstacles (trees) in the way, etc.
The kids take turns at throwing the frisbee at the hole. Every throw represents one hit, with the aim to get the frisbee in the hole with the minimum number of throws.