I found it:
Providence RECenter
7525 Marc Drive
Falls Church, Virginia
Here's the homepage, which includes the phone number, as well as price information.
Basically, you pay to get in, along with either $4 hour for the courts, or $20 for 10 hours. I did the math, and for 1 hour of play with the Fast Pass at the county resident rate, 1 hour would be about $7.27, not bad.
Forum:
Fairfax County General