Birthday ideas for boyfriend?

Okay so my boyfriend of 3 yrs' birthday is coming up in a month and I want to surprise him with a fun, romantic day out. Problem is I have no idea what to do. I really want to make this day awesome since he only gets one birthday a year (DUH). When I ask him what he wants to do he just replies with "nothing" or "idk". So I am going to start jotting down ideas and see what works best. I am thinking a day to the beach, movies, dinner, arcade? They all seem too generic and I want something we haven't done yet. We've done zoos, aquariums, basketball games (which is the only sport he likes), beach, knotts, disneyland, universal, sea world, all that. Anything will help!!!