Freestyle Love Supreme / The Reggie Watts Tangent, Assembly Rooms / Underbelly, Edinburgh, ****/ ***

Rap, rhyme and odes to Anthony Hopkins

The six-piece outfit rap and rhyme their way through suggested scenarios from the audience. We get a nice line about how one of them has drunk "ginger beer/ every day since I've been here" and a name check for Irn Bru - always guaranteed a laugh. A hip-hop ode to Anthony Hopkins manages to deliver a critique of the actor's performance in Nixon. And there's a brilliant riff about chocolate in all its forms delivered in an R Kelly stylee.

All of the performers, be they singing, rapping, on beatbox duty, or playing Brubeckesque keyboard phrases, have buckets of charisma, and their stage training is manifest as is their intelligence. Inevitably there were clumsy couplets, for example equating Tony Blair with Saddam Hussein. George Galloway is appearing at the Assembly Rooms later in the Festival, but for a moment it was as if he was already in the room. My only reservation, though, was whether there was enough stimulus to push this show through an hour. But I would wonder that about any improv troupe and the Freestylers get closer than most.

I wasn't humming any particular tune after seeing Reggie Watts, beat box stream maestro and stream-of-consciousness, spoken-word artist. I'm not sure I can say comedian. I'm not saying that I didn't laugh at his compositions, which at times reminded me of the excellent electro-rockers The Thrill Kill Kult and at other times Sly and Robbie, and, of course, Bobby McFerrin. I laughed when I could hear the words, not often enough.

As far as his banter between numbers was concerned it was hit and miss, so non sequiturs like: "Do you remember Star Trek? Yes? That's cool," hit the target while riffs on comically fertile areas like self-love, here involving wood - both the euphemism and the actual resource - waned early on.

Meanwhile, Reggie Watts' hair, part-Afro part-mohican threatened to upstage the man himself. The obscure cul-de-sacs that Reggie's patter was travelling down really needed to be delivered with a lot more menace to make them funny. I thought his affability diminished his "laughability", especially when contrasted to the sinister beats that he was coming up with.

'Freestyle' to 29 August, (0131-226 2428) 'Watts' to 28 August (0870 745 3083)