Nothing more I enjoy than New Years eve at a friends house with 20 other people. You can go to vegas anytime, it's not always easy to get 20 friends together in one place. If you have a decent size garage, get a space heater and set up the garage.
Edit: a game we played last year.
At 10:20 pm, take your first shot of beer, then take 1 shot every minute until at 12:00 you take your 100th shot. Wasted. I promise.
Also played a game where we lined up into teams and flipped some cups. I'll see if I can't find a better description somewhere, it's fun as hell.
Flip cup - Wikipedia, the free encyclopedia