Mark Clayton Southers ambitious little theater troupe summons the darker side of New Orleans on Fat Tuesday itself by staging all three parts of esteemed local playwright Frank Gagliano's Voodoo Trilogy.

At 6 p.m. Tue., March 8, see The Voodoo Parlour Marie Laveau. Set at the turn of the last century, this "unsung voodoo chamber opera" finds two morally and emotionally compromised denizens of New Orleans in the lair of the legendary voodoo queen.

I saw the show this past weekend, and Chrystal Bates is mesmerizing in the juicy (but by no means easy) title role. It's also probably the only play you'll see this year with live conga drumming. And the fabulous set, by local artist Vanessa German, is laid in Playwrights' brand-new couch theater. It's literally a comfy den of second-hand sofas on risers before the small-scale proscenium stage. Performances of Laveau continue through Sat., March 12.

At 8 p.m., there's a staged reading of The Commedia World of Lafcadio B., set in 1917. The play involves a charismatic con man, and again revolves around Laveau's spirit. The reading stars Brian Czarniecki, Karen Baum and Chris Josephs and is directed by Gagliano himself.

And at 9:30 p.m., the PPTCO main stage hosts the final performance of Congo Square, a drama with music about a gunman's standoff with police in 1970s New Orleans. The highlight here is Monteze Freeland, tearing it up in the main role as the gunman whose songs transport him into the personas of a half-dozen historic or mythic characters (including, naturally, Laveau).

Congo is followed by a Mardi Gras cast party on the Laveau set, with music by blues artist Leroy Wolford.

Tickets to Laveau and Congo are $17.50-22.50. Lafcadio requests a donation. Admittance to the party will be granted with a ticket stub from any one of the shows.

It's all happening at 542 Penn Ave., Downtown (www.pghplaywrights.com).