And my particular favourite: scheduling one off exam slots in medium sized rooms at unusual times of year (UK, further education, modular basic qualifications, externally marked exams). Last time, they put an exam in the room next to a music practice room...
Ah yes, spatial relationships between resources, the bane of every class scheduler across the world. The complexity of relationships between resources can explode so quickly to a degree that it becomes impossible to foresee every situation. So the software has two options: build in a Turing complete language to list this sort of dependencies (too hard to use for users), or allow large amounts of manual 'exclusion lists' for special situations. After a few years, those lists get so large that they start to contain internal conflicts. Then there are a few years of screwed up exam plannings, people get yelled at, new system gets implemented, and the whole circle starts again.
