Mini-tripods often collapse under the weight of any camera you'd actually want to use, but Manfrotto, known for its higher-quality camera stabilisation gear, has produced a mini tripod actually worth using. It adjusts easily, won't break after moderate use, and still fits in your pocket.
The downside? It does add a little bulk. To make a mini tripod solid, a little extra heft seems inevitable, but it's still highly portable. The rotating head makes for easy adjustments, and a small push button locks it in place once you have your camera right where you want it. Although designed for point-and-shoot cameras, this thing can handle DSLRs, too -- just don't put a giant lens on it. You can pick it up online for around $30.