Assignments on Javascript for beginners?

Can you suggest some good Javascript assignments/homework to C programmers, who are not familiar with Javascript? They are strong in C, hence basic Javascript. I need few JS related assignments which I can assign to them, to help them understand Web-Dev and Prototype concepts. I'm not looking for the tutorials which they need to refer. I think this question is little different from the question What’s the best way to introduce non-majors to HTML / programming?