Actually, that's the law: if you're employed as a programmer, any programming you do in your free time is copyrighted by your employer. At least in the Netherlands. (More info at http://www.iusmentis.com/copyright/crashcourse/ownership/ .) And yeah, that's pretty sick from an employee perspective, but great if you want to protect yourself as a company. When I was employed, I actually read my contract, so I had a side-note added with exceptions. If you're involved in any open source project, that's probably a smart thing to do. (Again, at least in the Netherlands, but I'm pretty sure that's not unique, since copyright laws tend to be very old.)
