Until recently, Philadelphians with a miniature-golf habit had exactly one option within the city proper: the 18-hole course at Center City's Franklin Square , with its family-friendly vibe and Spirit of '76 theme for tourists.Fortunately, that's no longer the case. Keystone Mini-Golf and Arcade , an indoor facility with nine holes and a grown-up, party-friendly atmosphere, recently opened at 161 Cecil B. Moore Avenue in Olde Kensington. And, in an unrelated venture, an 18-hole glow-in-the-dark putt-putt course known as Adventurer's Mini-Golf is due to open any day now at 38 Jackson Street in South Philly.Both businesses feature arcade games and Skee-Ball, and both offer dedicated party rooms. At Keystone Mini-Golf, which proudly advertises itself as a BYOB facility, the party takes place in a backyard gravel lot, open to the elements and outfitted with picnic tables.Keystone was started by Bucks County natives Bill Cannon and Drew Ferry, who stumbled onto their lightbulb moment after a session at a driving range in Southampton."We were walking back to the car and saw a mini-golf course," recalls Ferry. "We thought we could do a little spin on it [in the city], and do it BYO."The old-school, DIY-style course was put together in about six weeks with the help of Ferry's father, who works in construction. And while Ferry hasn't yet given up his day job as a mover, Keystone's first month went much better than expected."It's been amazing," says Cannon. "Yesterday, a guy came in with his girlfriend. Later at night, he came back with a buddy."On September 21 Keystone is hosting its Inaugural Mini-Golf Open with a $25 buy-in, free beer and prizes.Writer: Dan EldridgeSource: Bill Cannon and Drew Ferry, Keystone Mini-Golf