It’s hard to say who’s having more fun in this brainiac game store: the employees who are demonstrating the games, the kids who are playing them, or the parents who are (usually) patiently waiting their turn. Marbles, which sells unique puzzles, games, software, and other items to tease and exercise your synapses, is aimed at everyone from kids just starting to flex those lobes to seniors battling to keep the gears turning. Although the store has a number of locations across the country, including one in the Lincoln Square neighborhood (4745 N. Lincoln Ave, btw. Lawrence and Leland aves.; [tel] 773/784-7991), it all began right here, in Chicago.