Announcing Auto Silence on the Android Market!
The idea is pretty straight forward: get your phone to shut up by itself when you are busy. How? Using you Google Calendar App ( or from the Google Calendar website), set up those events during which your phone should be silent. Mark them by putting "[S]" (without the quotes) at the end of their names, and that's it. The phone will be silenced or put into vibration mode according to your preferences (you can change them from the application) when the events start, and the volume will be restored at the end of them.
If you are a student, set up your classes once at the beginning of the semester and forget about having to silence the phone for the rest of it.