Another vote for the Computer History Museum. I think the Tech Museum is kind of meh, but sometimes the traveling exhibitions are worth the price of admission.
The Winchester Mystery House is way overpriced, but I think it’s worth a visit.
If you like redwoods head for the Santa Cruz Mountains. Henry Cowell State Park is the most accessible, but other parks like Big Basin, Butano, Portola, etc are just as nice. You can go zip lining from tree to tree in Mount Hermon. If you like road trip kitsch and have a few minutes to kill, there’s the Bigfoot Discovery Museum in Felton.
A great day trip is to drive up 280 from San Jose, cut over to Pacifica and spend the day cruising down the coast to Santa Cruz, stopping wherever the mood suits you.
Stanford has a couple of good art museums–The Cantor and The Anderson Collection. There’s a cool Andy Goldsworthy “sculpture” there too, the Stone River.
edit–missed the bit about your wife not being a fan of museums.