Suncast 50 gallon rain barrel from Ace Hardware. It comes with an overflow hose and a short hose to connect to the spout at the very bottom (see the photo on the Ace Hardware website).

1. Ensure the mounting surface is level and will hold 450 pounds. I used cinder blocks to form the foundation and a 2×4 piece of wood to make it level.
2. Cut the long downspout (I used tin snips)
3. Cut in half the removed piece of downspout (short piece)
4. Connect flexible hose to vertical downspout
5. Connect short piece to other end of flexible hose
6. Aim and angle the new spout and hose to the top of the rain barrel

Monday, May 31, 2010, was the first day of rain after installation. Actually, I installed it WHILE raining. This probably made it more difficult, but I like playing in the rain.

Funny thing, but my 50 gallon rain barrel filled up completely in 60 seconds during the storm.

Photos on my Flickr.