While too many folks waste their youth in pursuit of MBAs, a few hardy souls continue to develop careers of meaning and merit. Such as “tiger choreographer” Khris Allen. Just as lawyering is a useless skill outside the circus of CourtTV, so, too, circus performers’ years of training equip them only to be circus performers. But what better expression of human potential than perfecting “hair-o-dynamics”? Or becoming a human cannonball? There is absolutely no reason for Miss Dolly’s Perky Pooches and Porkers, but aren’t you glad she took the time? Though its grand era is gone, the Clyde Beatty-Cole Bros. Circus continues, even managing to retain a whiff of the exotic, advertising The Khaskovas! The Kaliakras! And in the center ring, the Astounding Alex and Lucy! Perhaps even Keyser Söze will appear! Be astounded at 4:30 & 7:30 p.m. tonight at Bull Run Park, 7700 Bull Run Dr., Centreville. (703) 302-5510; at 4:30 & 7:30 p.m. Saturday, 1:30 & 4:30 p.m. Sunday & Monday at Quincy Park, 1021 N. Quincy St., Arlington. (703) 276-7444; and Sept. 8-10 at the Cascades, Cascades & Palisades Pkwys., Sterling.(703) 430-6789. $6-10. (Dave Nuttycombe)