The young attendees are split into rhubarb or custard teams, and are given red or yellow ribbon wristbands accordingly. They then set off into the Botanic Gardens for a game of, er, Calvinball. The only trouble is, the rules are missing. And so our three enthusiastic hosts – one referee and two team captains – are required to make it up as they go along, entirely in the spirit of the Calvin and Hobbes original. What ensues is sort of a Mornington Crescent of ball games, with toddling participation and yellow cards requiring offenders to sing the “sorry song” (which the FA should totally look into). Silliness, fun and a wonderful setting – it’s literally hard to lose at Calvinball.

Royal Botanic Gardens Edinburgh, until 27 Aug.
tw rating 4/5 | [Bruce Blacklaw]