Easy Science Fair Project Ideas

I've got ideas for just about every type of science fair project out there, but I realized I never made a category for what may be the most important type of science fair project: easy projects! I'm not talking about easy and lame... projects can be good and even award-winning without being complicated and time-consuming. Here's a collection of easy science fair projects plus a section for reader submissions where you can read about other people's easy science fair project ideas or submit your own.