semi-interactively explains how TLS works, very cool

Variables are the trickiest part of lambda calculus. And naming is the trickiest part of variables: the most complex code in our lambda evaluator is the part that renames variables to perform capture-avoiding substitutions.
Names are artificial tedious tags whose sole purpose is to aid human comprehension. Can we get rid of them? There ought to be a way to study computation without naming names.

Introspectable and extensible IDEs with logic programming

Fourier transforms are a tool used in a whole bunch of different things. This is a explanation of what a Fourier transform does, and some different ways it can be useful.

A website/game that allows you to create some DNS entries and see what happens.