Let’s say you’re just sitting around, and last week you find out that the Boerne, Texas, mansion belonging to retired Spurs great Tony Parker is on the market for $20 million. What do you do?Buy it if you have the money.I would if I could, but I’m a little short at the moment. Let me check to see by how much. Just as I thought — $20 million.Last year, for my birthday, spending time in the San Antonio area, I drove over to Boerne’s uncontrolled field and rented a plane. On the flight around the area, the guy I was ...