Best climbing gym near Lorton VA (southwest of DC) ?

Gotta take a work trip to Lorton VA southwest of Wash DC. Anyone got a suggestion on the best nearyby climbing gym?

Sportrock in Alexandria, VA. Not stellar, but decent.

OK thanks for info.

Rent / borrow a mountain bike and ride Fountainhead instead if it has been dry for a couple of days.

^^^^^^^ love the mountain bike idea. Looks like some major entertainment value. Maybe I'll get lucky and get done early with the project so I'll have some daytime for biking.