The streets are deserted, around the country merry bloaters sit in a state of drunken reverie before the TV. But into their well-fed heads drift nightmarish images. A howling mob pushing and scrabbling for a piece of leather, white bodies plunging into the icy depths of a lake, Welsh walruses running along the sand... Arrghhh. But these are not lurid dreams, evoked by double brandy and triple saturated butter cream pudding, they are real events in the Christmas calendar. Incredible though it may seem, there are some who exercise more than their eyeballs over Christmas. For whom a punishing five-film-a-day workout is not enough. In the Orkney town of Kirkwall, energetic revellers enjoy a mass game of street football called the Ba'. For more than 200 years, Kirkwall men have locked themselves into an enormous scrum and fought for hours over a leather ball. Split into "Uppies" from the top of the town and "Doonies" from the harbour area, contestants bump and grind around the town until the ball touches the castle wall or splashes into the harbour.
At London's Hyde Park, warm-blooded males from 14 to 80 hit the water when the Peter Pan club takes its annual dip in the Serpentine (right). The group's deceptively fey name comes from the book by founder member James Barrie. While The Spartacus Ice Breakers might seem more accurate, members swear by the rejuvenating effects of the annual baptism. Exceptionally keen swimmers could run barefoot from Hyde Park to Dyfed in Wales for a Boxing Day swim at Pembrey Country Park. The Walrus Dip off Cefn Sidian Beach attracts 100 fancy-dress swimmers. Past plungers include Little Bo Peep, the Owl and the Pussycat, and a Walrus. Organiser, Neil Perry, says the swim "blows off the cobwebs"; alternatively, you can draw the curtains and lay into that tin of Quality Street.
Uppies & Doonies, Kirkwall, Orkney, Christmas & New Year's Day 1pm; Peter Pan Cup, Hyde Pk, London W2, Christmas Day 9am; Walrus Dip, Pembrey Country Pk, Llanelli, Wales, Boxing Day 10.45am