[rvieira]

It's not the best project for your requirements (seeing the big picture and thinking deeply), but my go-to project for general-purpose languages is to implement a Markdown static site generator with a simple plugin system.

It allows me to test a few things I care about: filesystem operations, templating engine, reflection (or lack of), string parsing, testing, build systems. It also gives me a feel on the ecosystem (e.g. how many good quality Markdown parsers? Do I have to write my own).

Also, because I have a few of them I can make something of a comparison between languages for this particular use case (how long did it took me? how fast does it process the sources?)