There is no shortage of ambition over at the Source Theatre, where "Rosencrantz and Guildenstern Are Dead" kicked off a three-play repertory cylce last weekend.

This is the play that established Tom Stoppard -- with a witty vengeance -- and it remains one of the dazzling exercises of the modern English-speaking theater. What would "Hamlet" be like, Stoppard wondered, seen through the eyes of its two least important characters? Clearly, his heart ached for this tangential twosome -- trusted comrades of the hero who are assigned to inquire into his bruised state of mind, and later to escort him off to England and execution, but who wind up being executed themselves when Hamlet switches instructions on them.

Since Shakespeare offers utterly no grounds for assuming anything about Rosencrantz or Guildenstern, Stoppard could start afresh, and he decided to assume that, in fact, they had no existence beyond their status as supporting characters -- and deeply regretted it. In the play, they spend their time playing coin-toss games, asking broad philosophical questions about free will and determinism and the like, anxiously waiting for the few moments when Hamlet or Claudius will want something of them (or want nothing of them), and trying to remember which is Rosencrantz and which Guildenstern.

Director Tom Loftis shows a nice touch for the farcical side of Stoppard's work -- particularly the lowjinks of the players who perform "The Murder of Gonzago." Here, incidentally, a wiry actor named Stu Lerch livens things up considerably. The verbal wit proves to be a tougher challenge. As Rosencrantz and Guildenstern, Michael Genebach and Steven Mottram are a funny-looking pair, by reason, simply, of their relatively small stature in a generally tall company (either a shrewd casting move or just the luck of the draw). Mottram is also, unequivocally, a fine comic actor with a gift for the throwaway line.

That being said, it should be added that Stoppard calls for an extremely high level of acting that is consistently beyond the range of the cast now performing at the Source. Instead of dancing through the jokes and puns and verbal quagmires of the play, this cast is often trudging and stomping and getting its legs stuck knee-deep in the mud. But sooner or later. They usually manage to get unstuck, and so does the play.ROSENCRANTZ AND GUILDENSTERN ARE DEAD by Tom Stoppard; directed by Tom Loftis; with Michael Genebach, Steven Mottram, Nick Mathwick, Hilary Crosoe, Tom Pursley, Rick Levine, Patrick Miller, Stu Lerch, Gregg Walker, Joan Solomon, Deborah Glassberg and David Brown.

At the Source Theatre (in repertory) through May 10.