I really think you should visit the thread in my sig, which is stickied as well.
You have told us nothing to go by though...
Possible update refreshes like calendars, Facebook, etc...
Maybe the 2.1 update as of recent is trying to push to your phone but OTA certs aren't there...
We need more info - and if you need basics on kernels, heat, and battery, I suggest you read up as there is tons of info and threads on these subjects.