One rock star birthday party idea is to treat all of the guests like rock stars attending a major event. Include a list of actual rock stars with the party invitations and have guests select which one they want to dress up as for the party.
Place a red carpet at the front door with a few floor lamps along the edges of it. Ask a few friends or family members to play the part of the paparazzi. As guests arrive, have the fake paparazzi snap photos and yell out the names of the rock stars. Add a velvet rope around the red carpet to make it seem like they're getting access to an exclusive party.
Decorate the house with items that evoke images of a Hollywood event, such as movie posters, a lit stage and a VIP lounge. Once guests are inside and have mingled for a bit, get on stage and announce that the awards show is about to start. Make up a few funny award categories such as best look-alike, silliest costume, fan favorite rock star or most creative interpretation. Have the winners come up to give an acceptance speech and collect their prizes. Make sure, of course, that the birthday boy or girl is one of the winners.