https://grabcad.com/challenges/bike-accessory-challenge
Create an accessory that is 100% 3D printable that can help make your commute a little more fun or easier. Think of a product that is innovative and useful for those windy and rainy mornings, or that helps you bike on roads with heavy traffic, or something that will make your bike look or function way better than everyone else’s. This is a challenge just for fun so let your imagination soar.
The goal of this challenge is to design a bike (bicycle) accessory that can do one of the following:
1. Make your commute easier
2. Improve the capabilities of your bike
3. Make it more fun to ride.