While Denver residents clamor for the city to invest more in pickleball, one of the country's fastest-growing sports, another metro parks department has gotten into the game. APEX Parks and Recreation District in Arvada sponsors tournaments, indoor and outdoor play, mixers, camps and clinics for picklers of all skill levels. People can work with the department to put on their own tournaments or set up private lessons, while less-structure-oriented fans of the sport can drop in at one of the district's four pickleball locations for a game.