I’ve started a new side project named Crystal Koans, it’s a simple series of exercises organized as a big unit test suite.
The “koans” are heavily inspired by similar projects for other languages, but I didn’t found anything similar for Crystal. The project has been included in the awesome collection under the official Learning Resource for the language.
I’ll try to maintain and evolve it in the spare time, I hope you’ll find it useful, and any form of contribution is welcome.