Lots of Black Friday and Cyber Monday deals up at
www.mycheapvegas.com
For MGM properties, lots of free upgrades, and cheap non-refundable promos.
For the Caesars properties, just a tad cheaper than everything else, but definitely worth taking a look and rebooking if you've booked already.
Received an email from MGM newsletter saying the 27th will have some great deals too, so looking to see what will be posted then.