I have been working with javascript a fair bit lately. Previously I had tried to stay away from the language because of cross browser issues, and all the previous code I had seen was pretty ugly. Anyway, after playing with javascript I am definitely hooked. Some of the code can be very elegant and javascript's integration with HTML is excellent.
For example, you can add attributes to the XHTML elements as meta data for the javascript to process and effectively create your own HTML extensions. Take a look at "Lokesh Dhakar's Lightbox code":http://www.huddletogether.com/projects/lightbox/ to see an example.