I am proudly on my third notebook of cognitive science project ideas. These are supposed to be projects I can give students to work on, perhaps in classes. Some of these projects I have an idea of how they could be done, but some are just problems I think are interesting and as of yet undone.
For example, just now, while I was reading A Companion To Cognitive Science's chapter on language processing, I noted something interesting about the tip-of-the-tongue phenomenon. When we are trying to think of a word and cannot, it is distinctly different from the state of knowing that there is not a word for something.
So you might not be able to remember that a pasta strainer is called a "colander." You might search for this word in memory, in vain, but you know that there is a word. How? If you can't think of the word, how can you be so sure that there is a word? How do you know it's in memory at all?
The project idea is to come up with an answer to these questions.
Some might say (in fact, I expect many of my students to say) "this isn't a project; it's just a problem." True, it is just a problem. But I like open-ended problems for my students. In doing this project they might find the problem has already been solved, or there are some theories out there, or whatever. The process of finding this stuff out is valuable to them. And as a bonus, I get an answer, or a start of an answer, to my question.