[Kuytu]

If you're interested in C, one project could be developing GUI for some unix commands. At school we did a project once where we built a GTK app for creating logins on linux. There's many things you get to deal with like file handling and executing commands from code and so on.

One fun thing for learning hacking is trying to implement linux commands such as ls or ps. You get a little more intimate knowledge about the OS and you don't have to come up with specs because you already know what it's supposed to do :)

[nandemo]

I second the idea of implementing small utilities. It's also good when you're an experienced programmer and are learning a new language.

OP, besides that I suggest you try and write a simple, text-based chat program before trying to write an IM. For instance, start with a 2-way chat, add error handling, then start adding support for multiple users, chat rooms and irc-like commands.