The Gear Creator tool, which began as a school project in 2009, blossomed into a full-fledged tool in a few months.
Written in MEL script. Download the script and give it a try Here!

Gear Creator's highlighting features are:
1. In-viewport gear sizing controls
2. Procedural mesh and UV creation with multiple types of gears: Spur and Face gears
3. Intuitive orbital style orientation controls that keep the gear's teeth meshed in real time.
4. Animation ready via expressions, with rotation speed controls in the interface. Just press play!!
5. Real-time attribute sliders that can alter attributes for multiple gears at a time
6. Gear-by-gear creation style, where each new gear will snap to the side of the previous one
7. Random gear creation with value ranges for all attributes, creates a string of gears

Programming, Tools, MEL, Maya