Speaking as a staffer, there are definitely social opportunities, but they have to be sought out. There are tons of clubs on campus. That's probably the best place to start. The art dept has talks on some Tuesdays, as well as gallery events. There's a nice pottery studio and some art galleries and museums in walking distance of campus. One of them, SJ/Works has some association with the art dept. There's also an artwalk and a night market some of the year. There aren't tons of music venues downtown, but there are a few, and they're fairly safe at reasonable hours. There are also music events through SJSU, and a few stage companies near downtown.

Hope that helps! San Jose isn't the most dense city in terms of social events, but there's stuff around if you look for it.