I'm looking for a cute way to ask my girl to be my girlfriend?

I'm surprising her in San Francisco in a couple of weeks, and she has a dance recital, I'm going to watch it, and I do no know how I'm going to make it even more special to make it official between the two of us. I do believe me going up there is enough, but I want it to be memorable. I want to ask her the second she sees me, so I'm looking for any idea. Thanks to all help!!!