I've been doing a lot of work lately up at my son's junior school. They had been having a lot of strange network problems so I started helping. The more I dig, the more problems I find.
First it was just IP address conflicts because DHCP wasn't setup correctly. Next, it took me a long time to figure out why Active Directory Group Policies weren't being applied properly forcing me to learn several new utilities and registry hacks. It turns out that they didn't have write permissions to the DNS server they were using meaning the domain wasn't registered properly. Computer policies would work but user policies wouldn't. I've setup a local DNS server and am waiting for the go ahead to reconfigure all their machines.
In the meantime, I've learned a lot about Windows Server 2003 and how to administer a network. After sorting out their DNS and Active Directory configurations, I need to sort out their printing. I've gone as far as writing up an IT plan of work and started costing out a new server that they badly need. I'm quite enjoying all the tinkering.