I did a quick sketch for a friend and made this. Took about 2-3 hours.

Problems:
-Textures, Acceptable, Nothing special.
-Object would not work in real life.(but this isnt real life)
-Had to shy away from sketch for things i could not model(rips, tears, so on)
-Spokes of wheels are cobbed. They looks acceptable, but if you saw the wire....

I dont plan to go back and redo these... so it is technically the finished model.

Leaned:
-Several quick ways to create certain effects.
-Some texturing as opposed to throwing on a shader or lambert.
-Precision placement
-Conversions, Subd-poly and back.
-New rendering methods.
Heres the pic: