Friday and Saturday: Three years after giving an incredibly dark and moving performance at Orchestra Hall in honor of his late mother, Kate McGarrigle, the ornately voiced music heir will be showing off a decidedly lighter side with two distinct gigs at St. Paul’s equally elegant yet quirky Fitzgerald Theater, where his folkie father Loudon III is a regular. The first is an appearance on Minnesota Public Radio’s hit series “Wits” alongside “Flight of the Conchords” stalker Kristen Schaal (8 p.m. Fri., sold out). What with his recent marriage to Jörn Weisbrodt and their new baby daughter, Wainwright should have plenty of wit fodder. He returns a night later for a solo concert as part of 89.3 the Current’s “Current Sessions” series. (8 p.m. Sat. $39-$49. 10 E. Exchange St., St. Paul. 651-290-1200, or Ticketmaster.com).