A play about a 20-year class reunion may sound a bit, well, middle-aged, but Craig Wright shakes the old formulas like a doggy toy. Peter comes to the gathering thinking he might win back his old high school flame, Kari, even though their model "Cutest Couple" relationship broke down over a pregnancy. He not only tries to proposition Kari, but also steps out of character to ask the God-like Narrator to spin back the universe and start over. The shabby dance hall known as the Pavilion becomes a metaphor for theater, and for life itself. If that sounds like ponderous deconstructionism, Wright makes it exuberant and funny. It helps that Danny Scheie has directed such a solid cast: John Flanagan as the wistful, ex-popular failure Peter, and Deborah Taylor as the flinty but susceptible Kari are both engagingly unsappy. Joan Mankin also gives a tour de force performance as the Narrator and as 14 aging classmates, male and female, including a paranoid pothead named Cookie who's now mayor of the town in question (Pine City, Minn.). Even when technical problems plague the show, as they did when I saw it, Mankin improvises to make them look like part of God's (or Wright's) bewildering plan.