There are so many entertainment options in Las Vegas that is hard to know where to start. You can wing it, or buy a package party—though Las Vegas is about freedom to do exactly as you please.
It really depends on how tame or wild you want your celebrations to be. You could simply want to hit the slot machines and table games. Lady luck is sometimes coy, but fun to chase. If you are young at heart, perhaps you want your Las Vegas birthday party to include a trip to Gameworks or the Adventuredome. Las Vegas boasts numerous golf courses, so if that's your cup of tea you are all set.
Dining in Las Vegas is always a challenge—not because it is hard to find a good restaurant, it is just hard to choose! Every casino has its own restaurants and will be more than happy to reserve space for your Las Vegas birthday party.
At night you can catch a show or visit a club. There are myriad choices from upscale clubs and lounges at the Bellagio to just plain fun bars like Margaritaville. A birthday party is all about fun, so you could check out some of the magic shows offered by the casinos, or a comedy show, or one of the unique Cirque de Soleil productions. Just remember that the golden rule is to have fun and you can't go wrong!