This has happened to me a few times now. If I miss a call, or get a voicemail, the screen will turn on as usual but then it won't sleep until I either press the power button or unlock the phone. The screen will stay on indefinitely (on the lock pattern screen). This only started happening after I updated to 2.2. So now if I'm away from my phone and get a call, the battery will be almost completely drained by the time I get back to it (sometimes up to 4 hours later). This might also be happening if I get a calender notification too...anyone know what's going on?