THEATRE The Devils The Arches, Glasgow Dave's Last Laugh The Tron, Glasgow

Religion as this week's new rock 'n' roll may sounds like a ludicrous notion, but once upon a time so did comedy. Yet both have at times managed to drive young people into hysterical fits of libidinous excess and almost tribal hero worship. But when flavour of the month heroes fall they do so harder than most, and the only thing to keep the swooning going is an early, dramatic death. That way myth and immortality lie. Look at Kurt Cobain, Tony Hancock, Jesus Christ. All were victims of their own talent.

Both Grandier, the sensualist priest burnt at the stake in John Whiting's The Devils, and David Johnstone, the comic genius blown away in David Stirling's Dave's Last Laugh, could be said to be in the same boat. The Arches production of Whiting's play, based on true events in 17th-century France recorded much later in Aldous Huxley's The Witches of Loudon presents Grandier as a man of quiet charisma who genuinely believes in the redemptive power of sex, taken to a high plain by local widows and virgins alike. When the local nunnery go after their pound of flesh, he turns them down, setting into motion a hate campaign that drags all his indiscretions through the mud. Of course, politics and power games come into this too. Central government is looking to destabilise local autonomy, while a pair of jealous scientists - a catty Tweedle Dee and Tweedle Dum who'd scratch your eyes out with a mixture of clinical precision and delight - become prime movers in the conspiracy.

Played out in the darkest recesses of The Arches, Andy Arnold's production, featuring yet another unashamedly big cast, has much to commend it. The atmosphere it creates via its use of Gregorian chants and its mud-spattered environment, and the bitchy performances of Grant Smeaton and Ross Stenhouse as the scientists are bold strokes which colour a densely literary historical text. Yet it never builds enough dramatic momentum or gets scuzzed up enough to reach a fever pitch which threatens to spiral out of control and be genuinely scary. There are flashes, especially from Maureen Allen as the possessed Sister Jeanne, while welcome slices of irreverence and levity punch holes through any wilfully po-faced reading, but it simply isn't out on a limb enough to get to the heart and soul of matters.

The same might be said of David Stirling's play, which had a brief London outing last year, and is now presented in Peter Mackie Burns's new production for The Tron. In a series of scenes which zip across the years, it looks at the comedic "marriage" of two blokes called Dave, who from humble beginnings hit the big time before creative divorce beckons. The first Dave, Dave Grahame, is a natural thrusting wide-boy egotist whose exploits inadvertently fed the frailer, more sensitive, and possibly more talented David Johnstone's best lines, as truth becomes sit-com and sit-com becomes a mirror of both the Daves' obsessions.

Dave and Dave are not flat cap and whippets comics. Rather, they are products of the Eighties, when comedy became educated and sexy, more Newman and Baddiel than Eric and Ernie. Maybe that's why a play about how funny men tick doesn't really work despite strong performances from both Matthew Pidgeon and Neil McKinven. Maybe the Daves' lives are too comfortable from the off to make their indulgences anything other than a little bland. Yet despite the cheap-shot denouement and ill-advised use of video projections as an exposition of the insecurities and jealousies that lay at the roots of lingering laddishness, it's a far better prospect. So what we get is men behaving (slightly) badly on and off stage, yet without enough narrative thrust to drag it up to the level required to keep it buzzing along. Something else needed to happen to make it more substantial. Maybe one of the pair should have got religion, a la Bobby Ball. Now that would have been funny.

`The Devils' runs to 23 Nov (0141-221 9736). `Dave's Last Laugh' runs to 30 Nov (0141-552 4267).

Neil Cooper