SojaBird's MineCraft-Alpha Adventures, Minecart Launchstation
"During my two-weeks holiday @Ireland, I though 'bout making a launcher for my minecart ride. I drew lot's of layouts to see what could work. After getting home and asambling the tracks, it seemed that my booster didn't work properly so I came up with this!
The booster itself will always run. When the launchbutton is pressed, a track will flip, making the boostercart to make a bigger loop, powering the cart to ride in.

I do have to admit, the powerstorage at the other end of the track has some faws. It needs some more work, since it's experiencing random powerloss wich makes the cart go stand still.

Enjoy though!"