One is the Reduced Shakespeare Company, which has turned its attention from the Bard to the Bible. It is performing a 90-minute show summarising the Bible "from Genesis to Revelation".
Its three members begin their performance, part of the Fringe Festival, wearing only fig leaves. Later they don tunics and crowns. A running theme is the squabble over who gets to play God.
The show has already caused controversy in the United States, where it provoked objections o its "heresy". When they performed in Washington, the company received calls from a religious zealot posing as a journalist who attempted to get an "interview" before lambasting staff when his fraud was uncovered.
The actors argue that the production is harmless fun, but the Rev Bill Wallace, convener of the Church of Scotland's board of social responsibility, said yesterday: "Anything which attempts to trivialise faith and particularly the Christian faith in this day and age is deeply regrettable - especially at a time when more people are starting to show an interest in faith."
He would prefer such productions did not take place, he added. "It's pretty poor taste if that's all they can do to get people to watch."
Reed Martin, who stars at the Assembly Rooms in The Bible: the complete word of God (abridged) with Austin Tichenor and Matthew Croke, said of the criticism: "Our normal response is that people are entitled to their opinion. We'd love them to see the show and we don't think they'd think that way if they did - but those people never do."
Mr Wallace is equally concerned about the Irvine Welsh film The Granton Star Cause, which will get its world premiere on 21 August at the Edinburgh Film Festival. Described as a 36-minute piece of "rock and roll cinema", the film, by the author of the controversial hit, Trainspotting, depicts God as a washed- up and geriatric drunk.
It tells the story of Bob Coyle, whose life goes to pieces when his girlfriend dumps him, he loses his job and he is dropped by his football team. Things scarcely look up, however, when he bumps into God in his local pub, is changed into a bluebottle, and finds himself watching his parents having sex from their bedroom wall.
Fans of Welsh's work will also find it on offer in the Fringe Festival in Headstate, a revival of his first play. He wrote it in collaboration with the Boilerhouse theatre company, which describes it as "acid-house theatre" - half-play, half-rave.
The 50th Edinburgh Fringe Festival offers 553 productions this year, of which 58 per cent will be premieres.
Performers include Craig Charles, Jools Holland, the Chinese State Circus, Rory McGrath, Jenny Eclair, Jo Brand and Lee Evans.
Running from tomorrow to 31 August, it will also feature the Scottish Ballet, Midge Ure, an exhibition of the late Helen Chadwick's art, and cinema classics such as The Long Good Friday and Reservoir Dogs making their stage debut.