I started writing programs in Python to play with networking but I can't think of anything to do. I did a portscanner (it was with great restraint that I told myself not to scan Google because it's illegal) and was going to write a packet sniffer but decided it was boring. What other things could I write?
I was thinking at the moment to write something that follows all the links in a given HTML page and returns a list of broken links (links that result in a 404), or maybe something to find and download all the images on a website.