If you think that telling the time on a conventional clock is just too easy for you to be bothered with, then you need to get yourself one of these Equation Clocks. Rather than your usual 1-12 numbers (how boring is that?), the Equation Clock has a different complex sum that tells you which number is which. For example, the number 8 on the clock face is represented by the square root of 64 - don't tell us you can't work it out.

You might think that this sort of thing is solely the preserve of nerds and people who want to show off about how clever they are, but once you start to work some of them out it's actually quite fun. Attractively designed to resemble an old fashioned blackboard (to compliment the educational atmosphere, we don't doubt), the Equation Clock is not just for the smarty pants-wearers out there, it's a fun item for any home.