Why are hotel rates so high for Sept 23?

Hey All
My DH and I are going down to DL for the VGC opening abnd have our room confirmed for Spet 24 & 25, however we wanted to stay off site on the 23rd and found the hotel prices for some of the smaller hotels to be over $100. Does anyone know what is going on that day?
Thank you

Conventions? There is no way to know why room prices are higher, but it definitely means less rooms are available. The less rooms at any hotel, the more expensive the cost.