iPhone Feature: "Silent for XX minutes"

I live in Canada. I own many Macs. I don't have an iPhone, but I want one (they're not officially in Canada yet). I have a BlackBerry. What screws me up on a daily basis is when I go into a meeting and put my BB on "Quiet" and then forget to turn it back to "Normal". I regularly miss phone calls this way. My idea for an iPhone feature is that an owner be able to set their iPhone to be "Silent for XX minutes". This could be implemented as "Switch to XXXX mode for YY minutes, and then switch back". That'd be cool.