I don't write much code that would be helpful to others, but when I do, I'll include it here.
CLTcode.R, below, is a very basic simulation that builds intuition about the Central Limit Theorem. I used it to teach introductory quantitative methods to undergraduates at UC Berkeley. It is not complicated code, but early in my grad career, I didn't have the coding skills to write a simulation like this. So I thought it could be useful to early-stage grad students who don't yet know how to code but who need to teach CLT. I hope it helps someone trying to build student intuition about asymptopia!