Take your pick as per your individual liking. Masquerade Ball Party Theme This is one very matured and yet absolutely exciting birthday party theme for adults. All your guests would get to wear their most beautiful gowns and tuxedos for the party. You will, of course, have to make arrangements for some really pretty masquerades for all the guests, and prepare a nice stage where all the couples can do ball dance with their partners. The stage, music, and the masks are the heart and soul of this party, and if you manage to get this right, you would have a perfect setting for an amazing adult birthday party.