Primes is a collection of prime number finders in whatever languages I could get my hands on, and is one of my earliest projects. It acts as a handy simple Rosetta stone. It also includes a test driver to produce very crude language comparison benchmarks. Most of the project was written across 2004 to 2006 with a few new languages added later as I found them.
You can see them being used in the blog post Primes results for x86 vs. PPC vs. Arm