It happens once every 100 years – 7/7/7 is upon us, and as long as you’re not getting married or letting it ride in Vegas, Riverfront Park is the place to party. The Spokesman-Review’s 7 section and local promoters and venues are throwing a free, all-ages, all-day music festival in the park, pairing the Spokane area’s raddest rock bands and deejays with top-shelf national hip-hop acts, including Lifesavas, Blue Scholars and Blackbird. Nxstep Films and IMGXSport are bringing action sports demos, including a wakeboard “slider” pool. The madness starts at 1 p.m. At 10 p.m., the festivities move to the 7 after-parties 7 is throwing at 7 downtown Spokane bars.