Along the same idea as a wifi-based profile that changes depending on the access point connected too, I was thinking how about a profile that changes based on what time it is. E.g. If you go to bed around 12, you can have the tablet automatically switch to the silent profile from 12AM to 7 AM. After 7 AM it would switch back to whatever profile you usually use.

We've been doing something like this with cron already and just silencing or unsilencing volume based on time. How hard would it be to use cron to cover switching profiles?