What could i do for a 16th birthday party in San Francisco?

Im turning 16 in march so that kind of eliminates any outdoor stuff. Im going with two or three of my best friends and was thinking about going to the giant mall in San Fran and then going to Pier 39 and the Rain Forest Cafe later for dinner. What else could we do (besides stuff like ripleys or wax museum) that wouldnt cost a ton of money? thanx =)