Pleasance Cavern, Venue 33 (0131-556 6550) 8.55pm, to 30 Aug
Arj Barker fancies himself. He may spend the duration of his show trying to make us feel sorry for him, but it is obvious. He thinks he's it.
Take, for example, the way he goes overboard with a simulated orgasm - the punchline is a mere fumble in the dark next to his monumental climax. Or maybe it is the earnestness with which he embarks upon the closing song of the act, the subtext of which seems to be "You know, with these looks I could've been a pop star, but that would have been too easy".
There were other clues too. The repeated stories of sexual conquests, turned around to make Barker look forever broken-hearted. Or in the way he adopts that little-boy-lost look while asking the girls in the front row if any of them have been dumped since he was last here. As for the endless tales of drink and marijuana-fuelled nights out, they are enough to make you reach for the nearest bottle of whisky yourself.
Barker is an infinitely more enticing prospect when the action does not revolve around himself. In ranting mode, he is truly a force to be reckoned with, teasing out a succession of pithy one-liners from the most commonplace situations.
But the show is largely characterised by laboured delivery and a lack of direction that is underlined by a spectacularly uninspiring premise. It is all about the pressures of coming up with ideas for a new Edinburgh show. Barker's biggest problem is that he illustrates this point all too clearly.
Lyrebird: Tales of Helpmann
The Assembly Rooms, Venue 3 (0131-226 2428) 2.15pm, to 30 Aug
"Do you know the difference between fellatio and pork pie?' "No sir." "Here's my card, we're going to lunch."
It was the kind of outrageous statement in which the dancer Sir Robert Helpmann exalted, typical of the bright strident gestures he used to animate his life. He once claimed that he was born feet first, ready to dance the moment he sprang from his mother's womb. In his native South Australia, he cocooned himself away in layers of Max Factor, exploding into multi- coloured life only when his father found him a place with Anna Pavlova's ballet-company.
This is the kind of show that you will either love or hate. Tyler Coppin, writer and star of the work, conveys to an extent Sir Robert's dazzling and pioneering eccentricity, but the odd wonderful line aside, the unremitting high camp ultimately becomes tedious.
Cha Cha Cohen
The Attic, Cowgate
With two ex-members of the Wedding Present on board, Cha Cha Cohen were never going to slip by unnoticed. But the band's true asset is Jacqui Dulaney, a casino croupier from upstate New York whose edgy vocals carry an oppressive air of tragedy.
The stage is hers from the start. As she scans the crowd with a mixture of dispassion and disdain, we are each stared into submission. Even the band lurk deferentially in the shadows, safe in the knowledge that if they took their clothes off and set fire to themselves, all eyes would still be on their singer.
The music - laid-back grooves and trashy indie pop with a Bjork-like twist - appears secondary to her magnificent presence. Think Blondie, PJ Harvey or Courtney Love and you're only halfway to understanding her sinister appeal.
Indeed, if I hadn't seen Dulaney hooting with laughter only minutes before the show, I'd have assumed that she was a truly nasty piece of work. But like the front of their album - which shows Dulaney as a kitsch Virgin Mary figure - it's all fake. The kind of fake that is the making of a real star.