The coolest site for computer wallpapers is Digital Blasphemy. There is a limited amount of free wallpapers, but to be able to get any of the wallpapers, membership is required and so worth it. Check it out!
I work for a community college as their webmaster/web programmer and things tend to be very disparate with regards to systems. The student information system speaks its own language and interfaces with its own data. The Active Directory trees are updated manually each semester. The website has several internal and external tools that various users can use to achieve certain goals.
When trying to communicate across these and other involved systems, it can get a bit crazy. The Web tools are my primary concern. They require authorization granularity that just is not offered via our Active Directory (AD) layout. For example, some of those tools have some users that share a similar AD group and other users that do not. In addition, not all users of an existing group should have access to a given tool. Yet specific collections of users needs access to these tools and I am responsible for granting such access.