Since upgrading to 5.0.1 (or maybe it happened in 5.0?) I have been getting seemingly random audio alerts. They sound the same as incoming email notifications, but occur at other times as well. Seems to happen each time I pick the iPad up (maybe the inertial sensor?) and often when I touch the connector when it is charging. I think at other times too.
I have tried turning off all notification sounds, but no soap.