I'm enjoying these "in a single file" projects. They aren't often the paragon of best-practices but they make it easy for newbies to peep in on the syntax and see how complex problems can be solved. They are also usually a lot easier to try out, compile and deploy.

Here are a few others:

- Twitter Clone in Haskell in a single file - https://news.ycombinator.com/item?id=21616661

- MPEG1 in a single C file - https://news.ycombinator.com/item?id=20643336

- SingleFile CMS - https://news.ycombinator.com/item?id=18336986