My Android has a "Shush" app. If you turn your volume all the way down to vibrate it will ask you how long you want it silenced. So if you are going to church or in a movie for 2 hours you can set it for 2 hours and it will automatically turn your ringer back to full volume. I used to always forget and leave the ringer off and miss calls.
Great thread and app. I just bought it and im trying it out now. Replying to this thread through a remote connection on my phone. It's a liitle slow to catch up when typing but very nice being able to access documents!