Alice Jones' Edinburgh Diary: The Traverse scouts the fringes to make playwrights' dreams come true

One lucky playwright is to have a play they haven't written yet performed at the Traverse this month. David Greig and the theatre's artistic director, Orla O'Loughlin, have already commissioned 10 playwrights – including Alan Wilkins and Janice Galloway – to submit their 45-minute "Dream Plays", or scenes from a play they never dreamed would be staged.

One will be performed in the studio every morning over breakfast from Tuesday until the end of the festival. With 12 spots to fill, Greig and O'Loughlin have been scouting the Fringe for the final two writers. O'Loughlin has just found her newcomer, she tells me – Sabrina Mahfouz (above), whose debut play, Dry Ice, was directed by David Schwimmer.

Her second, One Hour Only, set in a brothel, is running at the Underbelly. "I loved One Hour Only, its energy and precision. It was like a little electric shock from London," says O'Loughlin. "There was something about it that felt contemporary and irresistible. I've just put the phone down and she's got a week to write a short script."

Great expectations for devoted sisters of mirth

It's hard work performing at the Fringe but Jessie Cave has the solution: rope in the family to help out. The actress, 25, who played Lavender Brown in the Harry Potter films, is performing her debut comedy show, Bookworm, at the Underbelly. Her sister, Bebe, 15, co-stars, her brother Jamie, 17, does her lighting and her mother is on props.

"She stays around for an hour after every show and tidies up after me," says Cave. "When I wrote the show I didn't consider it would take over all of our lives for an entire summer." It's not the first time the Cave sisters have worked together. Cave Sr will follow up the Potter films playing Biddy in Mike Newell's Great Expectations. Bebe will play the younger Biddy. "It was a really nice job," says Cave. "I'm not worried about watching the finished film because I know I'll enjoy watching Bebe in it whatever happens." Never were there such devoted sisters.

Izzard sets out to prove talent will travel with his global discoveries

Eddie Izzard (below) has always had a penchant for comedy in a foreign language, and now he's sharing his penchant for comedy from foreign countries with the Fringe. The comedian is co-producing two acts this year, both of whom he came across on his travels.

Michael Mittermeier is a German stand-up who has already supported Izzard at Soho Theatre. And there's a real buzz building around Trevor Noah, a superstar in South Africa, and his show about growing up mixed race in the apartheid era. Perhaps other comedians will follow his lead in putting their names (and cash) to their favourite rising stars at next year's Fringe.

From quick wit to quick-dry oil paints

Harry Hill's run of stand-up on the Fringe has already been and gone but his paintings are on show throughout the month on the second floor of a White Stuff shop in New Town. The comedian began painting in the early 1990s and it was down to Frank Skinner, apparently. "The breakthrough was doing his chat show," he tells the artist David Shrigley in The Skinny. "Instead of getting paid, you got a present, and the present was some quick-drying oil paints."