For me, fun is taking a program, language, whatever and making it do things it's designer never envisioned it doing. It comes in handy when I'm asked to do something a little outside the norm as part of my job.
My day job
12 Can a device pretend to be a USB keyboard? Feb 28 '12
6 Reading list manager? [closed] Dec 20 '10
5 paste text to bluetooth? Jan 7 '11