Apple founder Steve Wozniak helped raise the flag for the event he helped create. Last year it drew 60,000 people.
If you go, expect to see the cast of Star Trek: The Next Generation, the stars of Flash and The Walking Dead, and Astronaut Buzz Aldrin.
Wozniak said it was a no-brainer having a comic-con in the heart of Silicon Valley.
"All the Silicon Valley work. All of the engineering. It all involves a lot of fun and play. Geeks are that way. And comic con makes sense. Why was there no comic con here?" Wozniak said.
It all kicks off Friday. Tickets range from $10 to $99, with more expensive VIP options available.
There will be an outdoor festival that includes a science fair, beer and wine garden, and cosplay events.