The battlebot scene seems really cool, I had never heard of it before and I can be pretty darn geeky at times 🙂
The wild animal truck tour is absolutely amazing, something to do at least once while living in San Diego.
When I had vacationed here in the past (before becoming a resident) I was able to rent a small sailboat for the afternoon. Sailing on the Bay is just beautiful and a great way to spend a day. I am sure there are still marine operations that rent out sailboats.