Strange landing at SJC

Hello,

I just came back from a walk outside my office in Santa Clara. Around
3:00pm I saw something quite unusual - while all the planes from San
Jose International were taking off in N-W direction, there was a
single plane (something that looked a bit like MD-80) that seemed to
_land_ coming from N-W, exactly opposite the rest of the traffic.

I noticed the strange plane because it was going quite low and what
looked to me way faster than the usual. I can't see the airport from
here, but shortly after I lost the MD-80-like thing from sight I saw a
737 taking off - it looked like while one was landing on the west
runway, the 737 was taking off the east one in the opposite direction.

I've never seen anything like that. It's possible that the plane
didn't land on SJC, but it was awfully close to the regular flight
path. Is such "backward" landing normal? Was this guy having a
problem?

- Alex