I'm not sure about actual value, but the county-appraised value of my house has been uncharacteristically volatile over the past couple of years. From 2007-2011, it decreased modestly pretty much every year (1%-3%).
Then last year (when I thought the market was actually IMPROVING) it dropped like 6%. Slightly disconcerting, but I wasn't going to argue. This year, when I feel like the market has been pretty flat, it has gone right back up 6%+. Doesn't make any sense.