I was turned on to a great oral health tool by a friend of mine about a year ago. I'm one of those people that tries, really tries, to floss every night. Of course I don't usually succeed, but I try really hard and I'm doing much better now that I have one of these.
I used to floss maybe 3 times a month...basically whenever I wasn't too lazy to do it. Now I floss approximately 3-4 times a week because this little bugger hangs out in our toothbrush holder right next to my toothbrush so it's impossible to forget about it. It's easy to maneuver, pretty comfortable, and simple to change out the floss refill. It makes flossing exceedingly more simple than using regular old floss where you have to jam your fists in your mouth to reach your back teeth.
You can find these guys in any oral health care aisle; the only problem I've run into is that it can sometimes be difficult to find just the refills. Last time we needed refills we ended up buying a new flosser because the refill packs were missing from the section.
UPDATE: I stopped using these because my dentist noticed I had cuts in my gums. It's probably because the floss in the flosser is strung straight across and can't be manipulated to go around the surface of the tooth. So when you push on it even a little too hard it slices down into the gums. No bueno. Back to regular floss.