Interaction Design students at the RCA in London have created the Turning Back Time clock, a timepiece prototype for lovers.
"At the start of the relationship the couple separates the two clocks which allows them to each use the clock and also starts an internal time counter. Each partner can now turn back the time on their own and their partners clock by using the buttons on the keyring. This comes useful for instance after an argument. It is also possible to turn the time ahead in case you want to see each other earlier. By putting together the two keyrings again, the two displays become one which shows you the total time you have been in your relationship up to now." (via)