Culture
Silicon Valley culture is very geeky. In public, it's common to overhear conversations about programming, gadgets, science, or other geeky subjects.
Work culture
The work atmosphere at most tech companies is very casual. Engineers typically go to work in t-shirts. Work hours tend to be late - starting around 9:30am and ending around 6:30pm.
The demographics at most tech companies skew male. For example, Google released a diversity report and 82% of their employees are male.
Hobbies
Tech workers in Silicon Valley tend to have nerdier hobbies. You may see postings or clubs for drones, chess, board games, or gaming.
Media
Television. HBO's Silicon Valley is a hyeperreal parody of Silicon Valley. Read more on Quora about the comparisons between the show and reality.
News. Many techies in the area consume the following media:
Hacker News - created by Y Combinator, this is a popular news aggregator for tech entrepreneurs
TechCrunch - popular blog in Silicon Valley to follow for latest tech news
The Verge - popular site for tech reviews
Reddit - popular forum site
Blind - anonymous forum
Trivia
Santa Clara County has more EPA Superfund sites than any other county in the nation
In Terminator Genisys, the office of the evil corporation is based on Oracle's headquarters.
The first Pong game debuted at a bar that is now the Rooster T. Feathers comedy club in Sunnyvale.
The first integrated circuit was made in a building that is now a furniture store.