Photography. Haven't had as much time for artsy fartsy stuff with kids around (lots and lots of snap shot though). One of these days I'll have to round up the wife & kids, take them out to the park and shoot them...with my camera off course. I want to do some family portraits.
I also keep an aquarium. (freshwater, heavily planted) It is almost too much work to make it look presentable at least 10 hours of my week are consumed by that thing. I almost wish that I could sell the darn thing. Anybody want to buy a 75 gallon aquarium?
Photography used to be my hobby until my girls were born. While I still take pictures, its really only of them. I used to dedicate a lot of time, energy and money in the hobby but now my focus is spending time with them.
I also run daily, though I'm not sure if you want to call it a hobby or my fear of staving off obesity.