what we do is we go to the party store and bye a bag of balloons then when you're out there if you get two different colors (lets say a red and a green) you tie the two on a bush and as the wind blows they wiggle, and you make the red one as a terrorist and the green as a hostage and see of you can pop the red without popping the green. if you get bored then start a timer
its cheap and it it is reasonably fun.