What is timeprofile calendar and how to get rid of it?

A "calendar" called timeprofile popped up on my calendar list. It seems to be related to my exchange account but it was never there before. I tried to delete it but I can't seem to be able to. What's worse, ical keeps trying to delete it and now I get repeated alerts asking me to either "retry", "revert to server" or "ignore". But no matter what I choose, it seems to try anyway and the alerts keep popping up all day long. It's driving me crazy! Help me at least kill the delete job.