Based on the familiar Irish folktale, “How to Catch a Leprechaun” follows the comical adventures of the wistful minstrel Riley O’Really, who really wants to catch a leprechaun. He’s got everything he needs for his trap: a pair of sharp eyes, a good Irish folk song in his heart and, most importantly, an irresistible pitcher of green lemonade. The wee leprechaun who Riley catches seems more than willing to give up his pot of gold. But, it is his offer a leprechaun trick or a leprechaun treat? Tickets are $15. Performances are at the Keegan Theatre, 1742 Church St. NW, at 11 a.m., on Dec. 16, 17, 23, 26, 30 and 31. keegantheatre.com.