I modeled this speeder after Darth Maul's speeder in Episode I, but I added some extras.
The triangular pieces at either side of the front are for protection. To go forward, the rider simply has to lean forward. This speeder is supposed to be hovering, but I didn't have enough clear bricks to make that happen at the moment. You'll just have to pretend it's hovering... Anyway, enjoy!
Close up of the back. I used motorcycle bodies for the back. Also, the dual engines at the very bottom power the speeder.
Detail of the handlebars. As you can see, I made them out of rifles.
Detail of the seat.