Don't panic! That minute after you accidentally delete that episode of Dr. Who is the minute when you can get it back!

“Deleting a television program puts the show into the TiVo equivalent of limbo; while not actually deleted immediately, the show is effectively deleted, since it is no longer visible on your Now Playing List. In actuality, the location on the hard drive where the show lives is simply marked as available for reclamation; at any moment, TiVo can overwrite it with a new recording. This leaves you a small window of opportunity to reclaim that soon-to-be-lost show you deleted just a few minutes ago.” Source

Check out Deal Database's method here.