OOT - Need some Las Vegas hotel help

[Bigfoot]

I'm looking for some advice from anyone who happens to know anything about hotels or perhaps has experience with this situation. I'm looking to book a room at a hotel (in Vegas), but there are no rooms available for the Sat/Sun of the period I want to go. So I'm wondering if I book the Thurs/Fri is there any chance of going before checkout and asking the front desk/bribing them/etc. in getting a room for Sat/Sun. as well. I guess I'm wondering if the "no rooms" literally means there are no rooms and there is no chance of getting one, or if they generally will have a few held back or have cancellations and what not.

Any help would be great.