A streetwise exhibition

Now in its 20th year, this is a chance for children and adults to get out the chalks and express themselves on the theme of parks and gardens. Judges from the Royal Academy and Tate Britain will decide on the winners. All funds raised go to Duchenne Muscular Dystrophy.

Colonnade Walk, 123 Buckingham Palace Road, SW1 (020-7834 4844). Sat 4 Jun, chalking starts noon, judging 4pm, prize-giving 4.30pm, free entry, £1 for chalk and pitch.