Lately, I've been wasting spending time doing code golf at the (very informal) Anarchy Golf server. I don't claim to be any sort of expert on the topic, but here are some recent entries I've made, explained.

For those not in the know, the goal in code golf is to write the shortest possible program in language X that accomplishes a task Y. The golf server has a set of test inputs, and your program needs to produce output matching the corresponding reference outputs in order to be accepted.