Then we are going to the MNUFC vs SJ Quakes soccer game Saturday night.
Game Kastle of Santa Clara isn't what I think of as a "must see" (it's fairly small), but it's only 0.7 miles down the street from Avaya stadium. Isle of Gamers I haven't been to, but it is also close (about 3 miles) from Avaya stadium.
Gator Games and Game Kastle of Mountain View (unlike the Santa Clara store this one is larger and better styled) aren't far off the route driving down the peninsula from San Francisco to the stadium.
Check the store websites for hours and events.