This is clearly the year of the comedy Russells. There is the all-conquering Russell Brand, lunatic newcomer Russell Kane and, in the destined-for-greatness corner, Russell Howard. This gleeful 26-year-old has been around a while and has finally come good. An hour in his company is an unalloyed feel-good joy.

Howard calls his show Wandering, which describes his style, but not his mental energy level. His mind does not stroll, it positively pinballs. One minute he's describing a monk carrying a skateboard, the next he's chatting about doing press-ups in a disabled toilet.

In the past this blond Bristolian has been influenced by Perrier-winning Daniel Kitson, but a more natural reference point now is Ross Noble. Both have similar ways of picking out punters and building fruitful bantering relationships with them. Both also have a penchant for talking about unicorns, tigers and other unlikely comedy topics.

Despite its lightweight appearance, Wandering is anything but throwaway. At a time when comedy is becoming darker than ever, Howard, who clearly lives to giggle, passionately wants to make the world a happier place. And he manages it in spades with a show that will soften the most hardened curmudgeon.

• Until 28 August. Information: 0131 556 6550