I found this inexpensive downspout diverter on the web, and have been using a couple of them for a while.
It allows me to divert the rainwater onto my yard, but in the "closed" position, it still works as a downspout.... so I don't have to "disconnect" my downspout in order to use my rainwater in my yard (and help keep it out of the overtaxed storm sewer system). Wonderful for those summer thunderstorms, when the yard is so parched.
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Use our Save the Rain DiverterTM to channel water directly from your downspout fast and efficiently into your barrel, watering can or any water collection container. Close the diverter when your container is full and your downspout works as usual- no need to repair or restore your downspout.Our diverter fits standard residential downspouts, metal or plastic. (Preferred by customers with <3 1/2" downspouts)
Easy installation:
Two simple cuts in your downspout and then snap in the diverter.
Leave it in the open position when you want to store water, or fold it back to the closed position and your downspout will work as usual.Our Save the Rain DiverterTM galvanized steel and comes with a lifetime is made of warranty. It stands 11" tall and 3" wide
Update4/26/09 - you can find this diverter at: http://www.goodcommonsense.net/rnbrl.html [1]