Algorithms & data structures
I've been brushing up on algorithms & data structures for interviews, so I've been reading & writing lots of pseudocode lately to skill up.
However, I've discovered that writing pseudocode without any tests is a good way of writing buggy code, which isn't a great idea for interviews.
Hence, I decided to write some real code.
However, I didn't want to write verbose code.
So I chose CoffeeScript.