Do you save loose change? Not the most original idea, but one that works well for us, we use our vintage demijohn (which we found at the Melrose Trading Post during a trip to LA last year) as a sort of retro savings account - collecting all of our loose change and sometimes a bill or two, all while being pretty enough that it fits nicely into our decor.
We're not exactly sure what we're saving for - sometimes it's a new couch, sometimes a vacation. But we've gotten into the habit of cleaning out our wallet and pockets when we walk in the door and dumping their contents in, which hopefully means when we figure out what exactly we want to spend the money on there'll be a fair amount there. Then we'll just have to figure out how to lift the thing - we suspect it's going to be mighty heavy once full.
(Edited from a post originally published 2.25.2008)