I found out after a $150 "repair" that disconnecting the battery and letting the car sit for a few minutes, then reconnecting will also reset everything.
If you let the car sit too long with the battery disconnected, you will lost your radio station presets, but the garage door opener doesn't seem to lose its programming (it drifted once to the point where it only worked at very close distances, but that seems unrelated to a battery disconnect).
Jeff