Ruby is nice:

Enumerable - collect - a very useful method that returns an Array that is the result of running the block once for every member in the Enumerable object
Exception handling - Some of the nicest exception handling code I've seen in any language.
- Convert Ruby objects into a byte-stream. Really useful for sending large amounts of data to a webserver. assert_valid_asset uses it to send data to the w3 HTML/CSS validation server.