I need ideas.

I just finished reading Sams Teach Yourself C in 24 hours. Now I want to make a program (or project whatever) to implement all this stuff that I learned, now the thing is I CAN'T THINK OF ONE :)
Please I need some suggestions, please no games ideas for now, I like games to made using some graphics APIs, I am not a real fan of text games, I mean I want this program to be made using pure C.

You could write some sort of employee record keeper program. Its pretty dull programming but will test your knowledge I'm sure. This is just an idea anyways. Have the program write all of the records to a file and attempt to read in the records upon startup or menu option.

Just a thought.