Beer lovers: looking for something fun to do next weekend? How about a beer event in downtown Denver, just off the 16th Street Mall?! Next Saturday, May 21st, is the 4th Annual Brewer’s Alley, presented by Rialto Cafe. Brewer’s Alley takes place right next to Rialto, in the alley between Curtis and Champa. Brewer’s Alley is…