Last weekend my Lightroom catalog got corrupt and I had to restore from my most recent backup. My catalog options are set to backup once a week. Unfortunately it was almost a full week when the corruption occurred. It was quite easy though to restore. Rename your current catalog to save it (in my case - since I've got windows - it was in My Pictures folder\Lightroom\Lightroom 5 Catalog.Ircat) and then copy your backup catalog file (same name) from your backup folder location to that Lightroom folder. Everything was back to normal except for the picture imports and edit changes I made in that week. For me I had to re-import all my Roller Derby pictures. At some future time I will redo all the edits.

Lession - Make sure you set the catalog options to backup frequently.