Along the lines of your "offer withdrawn"; in 2004 I had an offer from Acclaim. We agreed on a number and HR said they would be sending me over the official offer letter and start date by the end of the week.

The week comes and goes, but no contact. The following Monday I give a call and leave a brief follow up voicemail, "Hey, haven't received the offer letter, just checking in." (something along those lines). Finally about three weeks later I get a call from this poor HR woman; she tells me that Acclaim has declared bankruptcy and she is really sorry she didn't contact me earlier, but that she had shown up to work one day and the doors to the office were literally padlocked shut and under guard since their assets had been seized for auction.