This is not something I thought I'd ever put on my "I want one of those" list: a thermostat. Not just any thermostat, I want THIS thermostat...
This is the Nest thermostat.
Not only does it look pretty slick, it's functionality is pretty damn amazing. You don't need to program it, just adjust your thermostat as you need it for a week and it'll learn and remember. Changing just once off won't confuse it either, but change it, say the same way on two successive Mondays, and it'll automatically remember to make that change for you on the third. Pretty damn amazing.
Check out the Living With Nest page for more details on how it works.
I think this would be a bit of a waste in our flat, so I'll add it to my "I want one of those when I build my own house" list.