Serena Davies reviews Improbable Frequency, (I Am) Nobody's Lunch and Taylor Mac

Three exceptional fringe shows are serving up variations on vaudeville. Irish company Rough Magic's Improbable Frequency is a crazed, delightful musical starring a machine called PAT - "Probability Adjustment Tank".

PAT is responsible for such surprising phenomena as the songs on the radio forecasting the weather and compromising neutrality in Ireland during the Second World War (where the play is set). Six flawless performers act out their unlikely tale in (unlikely) verse and song.

Some gags are pantomime: John Betjeman (yes, the portly poet) suggests they levitate because, "he doesn't understand the gravity of the situation". Others are more subtle: an Irish lass in carnal embrace with an English spy bemoans the fact that she's been "Infiltrated by British Intelligence: / Oxymoronic as well as a sin."

Also with a wit of its own is (I Am) Nobody's Lunch, a "cabaret docudrama" from the precocious young American company, the Civilians.

Drawn from real-life interviews that the cast made with everyone from a former Miss New York to a soldier, the piece tackles the ambitious question of how we know what to believe when everybody seems to be lying.

Its subjects range from lovers' mutual distrust to whether Tom Cruise is gay, and it is far funnier than its existential theme suggests. Yet its fierce engagement with the current crisis of confidence in American politicians is also deeply moving.

Add to this, disarmingly pretty songs and eccentric robotic dancing and it makes for a heady mix of poignancy and mirth.

Theatre or performance art ("which is just a fancy way of saying 'drag'") - Taylor Mac doesn't know what his shows are.

But this tall New York cross-dresser with a tiny ukulele is one of the most jaw-dropping things on the fringe this year, not least on account of his mesmerising beauty.

Bejewelled golden dreadlocks frame a face made up like a cross between a Venetian mask and David Bowie in his Aladdin Sane phase. In gorgeous homemade dresses, he sings songs demanding "the revolution will not be masculinised" and dissecting his love life.

It's camp and very naughty, yet suddenly devastating. This man in his perfect mask is a Pierrot figure for the modern age, all broken heart and outsider insight.

'Improbable Frequency' until Aug 27. Tickets: 0131 228 1404. 'Nobody's Lunch' until Aug 28. Tickets: 0131 226 2428. Taylor Mac until Aug 27. Tickets: 0870 745 3083.