So what has been your most useless project or big assignment for your courses?

Mine is very clear in my mind.

For Landscapes of Literature -- just look at the name! -- I had to spend two sessions in the Natural History Musuem totalling up to twelve hours looking at exhibits and taking notes to answer one hundred odd questions about the Caledonian Orogeny, various Silurian would-be-Shropshire-dwelling ammonites (what type of limestones do they form, eh?), and reliable index-fossils. Ten pages typed in single spacing, and nearly twenty hours wasted.