Photo by freeparking.
Advice weblog TipNut offers two different styles of trap—one for hanging, the other for positioning on the ground—to enjoy a wasp-free outdoors. To make either version, you'll need an empty two-liter soda bottle or any other plastic bottle that has an even width distribution along the sides, and a sharp knife. Once your trap is built, make sure not to overload it with bait (fruit juice and beer are both good options) because there needs to be sufficient air space between the bottom of the bottle opening for the wasps to easily get in.
Hit up the full post for the step-by-step instructions, then let us know of any other creative ways you've found to get rid of wasps and other outdoor pests in the comments.
Get Rid of Wasps: Traps & Tips [TipNut]