American has Non-Stop flights to Las Vegas on the cheap. Plenty of stuff to do even if you don't want to head up to Mt. Charleston or make the drive to Brian Head.
Philly to Las Vegas almost always runs $250ish — these cheap ski / skate flights save 40% and get you there Non-Stop on American.
Since there aren't many dates available on this one I am going to keep it short. Most availability goes down in January and February.