Hello guys. Does anyone have some ideas for some cool projects in C#?

Consider talking to your professor at school, he will definetly give you some ideas based on your knowledge... Your current knowledge is the most important thing. Don't get into something that may be too hard to solve. Of course, you can always try to make something big. Anyways you can always google what woud be good to do, what kind of app and on wich platform would be the best do develop it.