Like everyone else said it all depends on what you guys are like and into. I personally like quieter parties, some low calm music in the background so everyone can engage and chat and stuff still. I really value the ability to connect with people, or be a part of a group that is connecting, that way, versus something like loud music and dancing.
My friends and I use to get together and do cribbage tournaments. There were always a lot more than 6 folks but I bet you could do some sort of fun competition between all of you with cribbage (I just LOVE cribbage lol but there are a ton of other old lady card games that are fun). Another fun board game is Munchkins. I had so much fun playing this late at night with my friends.
If you guys are wanting alcohol I'd set up a small little area for a bar and have different things for mixers. I personally dont drink so I'd make sure I could have different fun drinks. I like to mix flavored sparkling water with bottled juices from Trader Joe's. They have this lightly flavored grapefruit drink juice and lime juice thing (I am such a hoe a for Trader Joe's).
Oh I almost forgot it's a BIRTHDAY! You have to have a cake and time for a song and presents .
I really hope you guys have fun. You're going to be out in a new place in a (hopefully) cool new hotel so I would try not to stress too hard, if you're the type to do so that is. It will be fun just by being somewhere new and being with good friends!