Kevin Buzzard's invited talk at CICM arguing that getting undergraduate mathematics formalised in theorem provers is useful and important. Slides at http://wwwf.imperial.ac.uk/~buzzard/one_off_lectures/ug_maths.pdf
of work I poured into our course blog. Every student contributed two posts to the blog, and I gave multiple rounds of detailed feedback on all twelve posts, learning a lot from the students in the process. and especially not Jekyll, since having a working Ruby environment is the hardest problem in computer science