On my morning commute there are a couple of big hills that kill me to try and keep up with the spin on the fixie, so I picked up a pair of carbon stoker pegs (they take the place of brake levers on the rear of a tandem) and brazed on some modified brake bosses on the sides of my Zion fork (think I voided the warrantee?).

It made for great coasting down hill this morning with my feet on the pegs. I just need to add a Gyro and I can start doing fixie tail whips.