Want a cool looking background for your site or favorite nanoblogging service like Jaiku, Pownce, or Twitter? Check out BgPatterns, a site that's not unlike the Web 2.0 stripe generator in that it lets you put together really slick looking repeating backgrounds with a simple builder.
To make one you just pick out what kind of pattern you want, and choose the colors. It'll blend all the elements together and give you a simple JPEG file you can use wherever. Advanced users who want a little more control can tweak things like scale, image rotation, and opacity for controlling how much of each element you can see. You're also able to change both the fore- and background colors with the proper HTML codes if you're trying to match them up to your existing color scheme.
When finished with any creation you can submit it for others to see or just squirrel away the tiny JPEG file. BgPatterns keeps track of both the latest and most popular combinations, which you can simply grab or port over to the editor to change it to your liking. Users can vote on their favorite designs and the daily winner gets front page promotion alongside the all-time highest vote getter.
Note: If you don't feel like using your creation for your site or nanoblogging profile, designs can double as desktop backgrounds as long as you've got it set to tile.