By demonstrating creative abuse of a language, one can better understand what the language constructs do and the scope of their capability. The comparable IOCC

By demonstrating creative abuse of a language, one can better understand what the language constructs do and the scope of their capability. The comparable IOCCC.org contest is a great place to learn C: sure the primary focus is making obfuscated code, and the audience marvels at the bizarreness thereof, but taking the time to pick a submission apart and figure out why it works (despite a host of reasons why you'd think it shouldn't) expands your understanding of the language. It's a great way to improve your language skills when you've reached the initial "I know language X" confidence.