Inexpensive strip room for Memorial Day weekend - Ballys.
 

I know this is a little far out, but I stumbled across this. With rooms in Vegas being pretty expensive nowdays, you kinda have to book very early to get a decent price.

Anyway, Hotels.com has a room rate for Ballys from May 25-28th that is $397. Ballys list rate is $467.

Book at Ballys for the list rate. Then submit their Best Rate Guarantee form. They will give you the $397 rate minus an additional 25%. So your rate will be $298 or so for 3 nights on a very busy holiday weekend. I've done this before...it requires jumping through some hoops. I wouldn't expect the rate to last beyond noon tommorow, if that, so it behooves you to book if you think you might go that weekend.

Ballys is located mid strip, across from Bellagio and an easy walk to Mirage or Venetian. Wynn and MGM are a bit further and probably require a short cab ride. Ballys is a decent though not great hotel with large rooms. Sleeping four in a standard room is not a problem at all.