There's an axiom about comedies not aging as well as tragedies. Everyone understands why the Trojan women are upset, but Lord only knows what might have made an ancient Greek chuckle.

That sweeping standard generally holds for Shakespeare. Most high schoolers get Hamlet's existential keening; A Winter's Tale consistently proves a bit tougher to decipher. The clever nuances that an Elizabethan audience would immediately appreciate sail over the heads of all but the most well-schooled contemporary watchers. So the near-eternal hilarities of crotch-grabbing and drunken tomfoolery must be played up, the costumes made outrageous, and the set enchanting.

Pig Iron Theater's production of Twelfth Night effortlessly delivers on all of these levels, the play opening with a live band, paisley and fedora-clad, ambling around a huge skateboard ramp set against the wall to facilitate amusing entrances and exits. Lantern-jawed Duke Orsino (Dito van Reigersberg) struts on stage, shirt unbuttoned to the navel, his opening monologue aided by his exaggerated languidness.

Pig Iron chose wisely with Twelfth Night, a play that can be easily tailored to modern sensibilities. Not only is it full of excellent one-liners ("Many a good hanging prevents a bad marriage"), but after Shakespeare sets up the usual complex lovers' quandaries, he clearly becomes more taken with the comic antics of the secondary plot.

The play's passions are unconvincing: Even though many of the characters are middle-aged, they all fall in love on a dime. But that doesn't matter. They create a fine scaffolding on which to hang the antics of the drunken knights, Sir Toby Belch (James Sugg) and Sir Andrew Aguecheek (Andy Paterson, sounding a lot like Charlie from It's Always Sunny in Philadelphia).

The plot is entirely trivial, and that's the point. The only note of viciousness in the whole production is the aforementioned revelers' systemic attack on Malvolio, the steward of a great lady (expertly played by Chris Thorn). He first appears, in his haughty self-regard, as though he has wandered onto the wrong stage. Puffed up with pomp, he wants deflating. The play needs him to be brought to earth, dragged down to the same absurd level as the rest of the cast. "Dost thou think, because thou art virtuous, there shall be no more cakes and ale?" Sir Toby taunts. The one figure who seems immune to cheer is brought low; his piteous humiliation - tricked into a tight neon outfit that would make a Mummer proud - is a delight to watch.

Despite the outrageous costumes, excellent set, and roving live band - the West Philadelphia Orchestra, in an essential performance - Pig Iron actually plays Twelfth Night just as the man wrote it. And that works better than it might in, say, A Midsummer Night's Dream, the most overplayed of all the comedies. (I was exposed to such an extent in grade school that I'm still bored unto death at the very mention of Oberon and Titania.) The intertwining love quadrangles are hard to translate ably to a contemporary audience, which is one of Twelfth Night's great virtues. After Orsino's initial monologue ("If music be the food of love, play on," etc., etc.), we are largely spared his pining.

Samuel Johnson dismissed Twelfth Night because the central romance fails "to produce the proper instruction required in the drama, as it exhibits no just picture of life." But that's just the reason why it remains such good fun. The plot doesn't make much sense. Why wouldn't the nobly born Viola (Kristen Sieh), who has just survived a deadly shipwreck, just tell the Duke (who knows her father) her situation and have him take her in? Don't question, just kick back and have some more cakes and ale.

The triviality of Twelfth Night is especially fitting for this time of year, when we are meant to have a good time but too often let the Malvolios in our lives, and in ourselves, spoil things. December is jammed full of holidays, parties, and other opportunities to act the fool. But it is easy to lose sight of good cheer amid the approaching end-of-year deadlines and stultifying sorties into Christmas-thronged malls. Pig Iron's production can serve as both an admonition, and an occasion, to allow yourself to play the riotous knight (at least for a month).

Twelfth Night plays through Dec. 22 at FringeArts, 140 N. Columbus Blvd., Philadelphia. For tickets, call 215-413-1318 or visit fringearts.ticketleap.com.

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