Long Island’s premier competitive running event is here: RXR Long Island Marathon Weekend, Friday, May 4-Sunday, May 6, includes the 26.2-mile marathon, a half-marathon, 10k and 5k races, plus a 1-mile run and Kids’ Fun Run. Runners can check in and pick up their race bibs during the Sports and Fitness Expo, 3-8 p.m. Friday, May 4, and 10 a.m.-4 p.m. Saturday, May 5, at Mitchel Athletic Complex, Charles Lindbergh Boulevard in Uniondale. (There is no race-day check-in.) Catch up with the runners as they finish at Eisenhower Park on Sunday for post-race festivities.