I'm with Joe, I was just on SkyAuction.com, there are some great deals, I think seven nights at AmeriSuites was going for $33 night a few minutes ago.
If you have time to surf some sites, private home owners are always running last minute deals on rental cancellations.
Best of luck! You can also look on roomsavers.com. Find out what hotels are currently offered. The partners usually stay the same. Sometimes you can even make ressies.