Corpus Clock

The Corpus Clock sits on the outside wall of Corpus Christi College in Cambridge city centre, and it's genuinely odd in the best possible way. Instead of numbers, you get a mysterious golden face with a creeping line that moves around its circumference - it's meant to show the passing of time, though watching it actually work requires more patience than most of us possess. The real star is the Chronophage, a mechanical grasshopper perched on top that snaps its jaws shut every second, as if time itself is being devoured. It's free to stand and gawk at from the street, which is fortunate because you won't get inside the college just to see it.

This one works best for people who like their art installations unsettling and conceptual. Kids find it creepy rather than engaging, which is fine - it's really for adults who appreciate John Taylor's rather pretentious statement about mortality. History buffs and anyone into modern sculpture will get more from a proper look than the casual passer-by.

Allow ten minutes maximum unless you're genuinely fascinated by the mechanics. It's free, always visible, and honestly worth a five-minute detour if you're wandering Cambridge anyway. The nearby college buildings are worth a walk around too. If you're based at one of the caravan parks - Cherry Hinton, the Camping and Caravanning Club site, or Highfield Farm are all within three miles - Cambridge's city centre is easily reached on foot or by a short drive, making this a decent rainy-afternoon filler between proper attractions.