An interesting trend has emerged this second to the last weekend of summer: Old coots are selling tickets. Though headed by the cheerleader comedy “Bring It On” and the Wesley Snipes spy thriller “The Art of War,” this weekend’s box office chart also reflected decent showings by “Space Cowboys” and “The Crew,” both of which star a geriatric band of merrymakers. (The cumulative ages of the stars of the latter two movies, whose casts are headed by Clint Eastwood and Burt Reynolds, respectively, would impress Methuselah.) The weekend’s Top 10, according to early industry estimates: