Flowers can do a lot to brighten up your home until they start to rot and die. While they're not going to live forever, according to green living blog The Daily Green, you can provide a little life support with sugar and vodka:
Add a few drops of vodka and a teaspoon of sugar to the water in your flower vase. It should help keep your flowers fresh longer. Change out the mixture with fresh ingredients daily.
Seems like a pretty simple way to get a little more out of your flowers. If you've got the touch of death rather than a green thumb, this might be worth a try.
10 Weird Uses for Vodka [The Daily Green]