Ring-ring! Ring ring! What's that sound? It's the sound of ten students from London trying to get to grips with an un-winable war. Don't Call Us, We'll Call You centres on that dreaded phone call families of servicemen are terrified to receive, and its frankly over-excitable marketing campaign details how the big red instrument can become 'an object of hate, fear, desire and even lust!' for those left behind.Exclamation marks aside, the lust is quite funny, with a bravura performance by Holly Williamson adding new meanings to the term 'phone sex'. Almost every movement and Vicky Pollard-style vocal tic seems to be a hit with what I suspect is mainly a home crowd, but I think she is very funny.Other performers, their roles numbered from 1 to 10, have intermittent moments of good comic acting, from Charlie Butt's lisping, secretarial recording of a dating website video clip - 'I like to brush my hair while listening to Enya' to numbers 5 and 6, competing to show their affection for the phone and by extension their endangered loved ones in a series of increasingly ridiculous displays of oneupmanship, all accompanied with a catty flick of the eyes.When Tom Machell's script is funny, I liked it, but the moments where the humour drops are face-gnawingly bland, their soapy predictability about as emotionally wrenching as a damp flannel. These 'when's-daddy-coming-home' sections threaten to derail the play completely by bluntly announcing its central theme, which is served far better by suggestion and humour, the various narratives circling around the phone like matter orbiting a black hole. The 'emotive' sections are the equivalent of jumping into the hole with a banner saying 'OUR BRAVE BOYS.' War blows we get it. But at least the acting's fun.