The reuleaux tetrahedron is a pretty cool shape. It's a solid of constant width.

This is a basic 2x12 speaker cabinet I'm designing for a friend.

The model isn't complete, nor is the general design, but I thought I'd share.

I love my makerbot, but the ABS fumes are a bit much for me. I needed a bit more ventilation, so I started using fans. They were large and loud, however, so I went out and bought a fan. I got a 120mm computer fan (ThermalTake Hightst Performance 120mm fan) and designed these brackets to hold it. It sits in thee opening on the left side of my 'bot, and blows most of the fumes out the window. :D

Video of the print: youtube.com/watch?v=Q8w2asyvB1U

This is a cool robot wheel I designed during my lunch period. :) It is scalable, But if You scale it, remember to adjust the axle hole size. I usually make mine at 50% size.

This might actually make a decent flywheel if made of metal.
It was supposed to be a pulley, but made a better wheel.

UPDATE:
I added a wheel with five spokes instead of three. It is also smaller.

This is a holder for a NEMA 17 stepper motor. It should be compatible with most motors of that size, but I'm not sure.

UPDATE!!

This was designed for wall mounting the motor, for an AS220 style drawbot. Since my motor has a small shaft coming out the back, I designed some spacers to allow the mount to sit flat.

This is my take on MakerBot's Mechanical Endstop. All the traces are on a single layer, and the silkscreen is optional. It is easy to make by hand.

The output pin is normally low, but goes high when the switch is triggered. The resistors are surface mount, but can be soldered easily by hand.

This is a breakout board for the L293D motor driver chip. It is single sided, and therefore very easy to make. If you don't have EAGLE, you can download the PDF version of the layout.

UPDATE:

I've uploaded gcode for milling the pcb. If the settings aren't optimal for your machine, it should be fairly easy to modify the files.