There's been a lot of speculation about exactly what Stonehenge was — a religious altar, an alien monument, a boring pile of rocks. But consensus seems to be it's just a big calendar, so we find it entirely appropriate that thousands of years later someone would miniaturize those ancient big blocks and turn them into a timepiece. The Stonehenge Pocketwatch unfolds to reveal a tiny replica of the stone circle as it looked when it was first built. To tell the time, just hold the watch in the sun, attach the included gnomon (that's the rod sticking out of the middle), see where its shadow is cast, take into account which way the compass on the lid is pointing, and… uh, probably do a little math. Mercifully, there's also an analog watch on the underside of the casing for "confirming your calculation." Still, it sounds like some fun brain exercise, plus you get a watch that can predict the summer and winter solstices to the minute. Finally! — Peter Pachal

ThinkGeek, via Oh Gizmo!