In a fit of madness, I have agreed to deliver a 50-minute lecture on type classes to an audience of undergraduate students. These students will have seen some simple typing rules for F2 and will have some exposure to Hindley-Milner type inference in the context of ML. I am soliciting advice about * Cool examples of type classes * Papers I could read to explain how to implement type classes, especially if I could show the `dictionary translation' which is then followed by ordinary Hindley-Milner type inference * Any other material on which I might base such a lecture I'm especially in need of a guide to the literature, as the `Haskell bookshelf' at haskell.org is silent on the topic of type classes. Please send me your recommendations. Norman Ramsey