A project that will take you multiple weeks and trials to complete. You should be building something, creating something, makings something better. Below are some student samples from past projects.
Although you will need to do some background research to get started, this is NOT your genius hour project. You will need to do something with the research you do.
For example it is NOT a genius hour project if you only do research on how to make brownies and find a brownie recipe to put in your presentation. If you do not make the brownies (and preferably 3 or 4 versions of the brownies) then you you have done a research report and not a genius hour project.
Found a brownie recipe
Did a presentation about a movie
Tell me all about video games (ie fortnight or minecraft)
Make several recipes and pick the best (bring samples the night of).
Research about special effects and try your own green screen or stop action movie.
Try to code your own animation; learn about jobs in the industry and write to creators to "interview" them about their work.