[resc1440]

Also MarkupSafe - https://github.com/mitsuhiko/markupsafe

It's a little bit meta, but I had lots of "wow" moments. Also, it's a nice example of using C to speed up certain operations.

[nekopa]

Thanks for this recommendation. I don't know if I will check it out right now, but it is on my list now because I am hoping to integrate C in Python when needs be. But I don't want to jump the gun :)

[njbooher]

For that you might want to look at Cython.