The Instructables Remix contest asks contestants to find an existing project on the Instructables site then remix and build upon it. Entries have to include credit to the original source and directions for replicating the remixed version of the project. 19 prizes are being awarded with the top prize being a $500 Amazon gift card. So far there are only 13 entries with 46 days left to enter. The contest is open to students over the age of 13.
The Remix contest is one of eight contests that Instructables is currently hosting. Some of the other contests are a pumpkin contest, a Halloween costume contest, and a "back to basics" contest with a STEAM theme. Take a look at the contest page on Instructables to see if there is something that will inspire you or your students.