Goal: a power grip/holdfast style toe strap that's:
1) tough
2) water/rust proof
3) as close to clipless as possible
+ cheap, green, and a fun little project

Tools
1) scissors
2) wrench (i used pedal lever that's thinner than a regular wrench, but any wrench will do. 15mm is standard for bike pedals)

Materials
1) zip ties (I used 100lb tensile strength metal ties on the pedal not shown, and 50lb tensile strength nylon/plastic ties for the one in this instructable)
2) obviously a tire (I used ~18" length of 23x700 road bike tire)
3) more obviously, pedals

Step 1: Attach Strap to Pedal Axle

1) Remove pedal from bike with wrench
2) Cut a hole in the tire with the scissors so that the tire is not touching the axle at all. If they are making contact, you will hear an annoying squeaking sound while you ride as the rubber brushes against the metal.
3) Put the axle through the hole so that the outside of the tire will now be on the inside against your foot, and the inside of the tire will
4) Strap it down tight against the pedal with zip ties

Step 2: Attach Strap to the Other Side

1) Build a "buckle" using another piece of tire about 1x3.5"
2) Thread the loose end of the strap through the "buckle", around the far end of the pedal, and back through the buckle. If I wasn't clear, here's a quick skitch
3) Put the pedal back on, adjust the strap and ride