I'm a commuter; I mostly ride around the city to get to work, go shopping, visit friends, and stop by the pub. I have basic cycling skills down; proper mounting and dismounting, signaling turns, standing on my pedals to sprint up short hills, and so on. But I've seen some more advanced skills and tricks that I don't know how to do, such as bunny hops, track stands, and the like.

What advanced cycling skills are useful for a commuter or city rider, and how can I learn to do them? I'm interesting in things that are useful, not just showy, and interested in city riding, not mountain biking. For instance, learning to bunny hop might be useful for that one point where the curb cut to get back on the bike trail is half a block down from where the trail actually is.

For each trick or skill, describe it and how it's useful in the city, any limitations it might have (can only be done on a fixie or a mountain bike with front shocks, or should only be done when you have plenty of clearance on both sides, etc), and describe how to learn it, either directly in the answer or by referring to a good resource on learning it elsewhere.