Some of the lower rates seem to be selling out, I think this was also listed on Travelzoo which has a big following.
For $39 per night, stay in the center of The Strip at a Las Vegas hotel that can regularly run as high as $139 per night.
Travel select dates through August:
April 18-21, 24-27
July 4-7, 10-12, 17-18, 24-25
Aug. 21-25, 28-31
Combine the above rates with surrounding weekdays or weekends and still save.