Copied shamelessly from TableTalk, the Salon.com blog:
For those who've jumped on the fizzy water bandwagon, here's a new soda.
1.5 c chopped rhubarb, 1.5 c water, 1 c sugar -- bring to boil, simmer for 15 minutes.
Strain into a jar. Let cool. Pour a couple of ounces over ice in a tall glass and fill up with fizzy water.