Last server move I forgot to stop mysql before I copyed the db (should've used hot copy but decided to just copy the files instead) - destroyed the post table thought everything was gone (1.5 million posts) and the last back up failed so I was left with a week old back up. My members would've murdered me if I had used that.
Managed to fix the tables in the end but must've lost a couple of stone in sweat doing it.
Here's me panicking on vb.com
http://www.vbulletin.com/forum/showthread.php?t=291030