With its elements of geometry and physics, billiards recalls the golden age when well-rounded scientists and philosophers carried big sticks with which to whack whatever they pleased. Join the ranks of Plato and Teddy Roosevelt with today's Groupon: for $15, you get $30 worth of billiards and comfort fare at Flat Top Johnny's in Cambridge.

A past winner of Boston magazine's Best Pool Hall award, Flat Top Johnny's complements its felt-topped tables with home-cooked food and a laid-back atmosphere. Games of billiards ($12 an hour/table) at any of a dozen tournament-size pool tables send balls bouncing while several old-school pinball machines mutter nervously nearby. Fuel a rousing game of eight-ball with an appetizing bowl ($3) or cup ($5) of homemade chili, complemented by Johnny's house-made corn bread, or with a crew of sandwiches, wraps, and snacks from Flat Top Johnny's menu. Johnny's can stuff grilled chicken and feta cheese into a corner pocket of ciabatta bread ($6), or mix pork, beef, or veggie sliders with two other identical sliders (three for $7). Toast an evening of trick shots and twisted dough by hoisting a beer mug filled with pretzels ($3), chased by a shot of mustard.