Well for my birthday back in October it was nice just to be with a friend or two, we went to Niagara Falls (I live close to there) had dinner and went to the Midway to play the arcade. Do something like that, be a kid again, have a nice dinner, eat a giant dessert, tell them it’s your birthday most places will do something awesome for you. Maybe hit a city that’s not too far away from you and just wander the streets, go in and out of little shops and just explore with a good friend. It’s fun =) And if you find an arcade then go for it!