Since Simpson's Paradox has been discussed here recently (and not so recently), I thought I'd share this interactive1 infographic that I found via the FlowingData blog. I already understood Simpson's Paradox pretty well, but playing with the sliders helped me get a more intuitive feel for it.
I expect similar tools would be helpful for explaining Bayes' Theorem and some of the other things we talk about on LW (like Pareto efficiency and Nash equilibria). Do such things exist?
1 The interactive part is farther down the page.