Mike Rizzo’s tenure with the Washington Nationals may be done, but the longtime team executive is providing the club’s fan base with one more memory. Rizzo, who was fired last Sunday as the Nationals President and General Manager, has invited fans to enjoy a round of beer on him during a Monday happy hour as a token of his appreciation. In a social media post Friday, he thanked the fan base and invited them to grab a “Round on Riz,” from 5 to 7 p.m. at Penn Quarter Sports Tavern or Walter’s Sports Bar. The post came from the Rizzo Family Foundation, which aims to help pediatric cancer patients and their families.