Two rooms in my basement. It would be every single room in my house but the wife won't allow it. I have a pin that I ran out of room for up at my parents house and yet another pin I ran out of room for up at a friends house, so maybe that counts as four rooms in three houses?
10 years ago I only wanted one pin for my rec room. I was warned that he who buys one pin will inevitably buy another... and another... and another. Now I'm up to 8 (if you consider Zizzle's and Star Galaxy 'real' then its 11).