Ricardo Tomasi has a neat post (published 18 months ago!) featuring some deliciously succinct coffeescript:

You may have read "10 Scala One Liners to Impress Your Friends" at Marcus Kazmierczak's blog recently featured on HN. Although I don't know Scala (or Java), it all looks quite nice, so I decided to impress my friends too - folks go from Java to Scala, we go from Javascript to CoffeeScript. Assume node.js as the environment for all examples.