Things to do in 2 weeks vacation in San Diego??

Hello everybody,

I am visiting SD for the first time and I'm really excited about it. I want to know what sort of things I must do during my 2 weeks trip ( starting from 26th April). I am mainly interested in some outdoor activities, preferably in groups. Would love to explore SD in the best possible way and I want this trip to be a memorable one. Your comments, suggestions etc will be greatly appreciated!!

PS: are there any internation event happening during this time ??
BR
Ayesha