Why JavaScript is one of the coolest languages around.
Every time I go back to coding any JavaScript I discover new things that I never knew were there. It's like the language that keeps on giving. :)
For a great tour around the language check out this site:
http://www.crockford.com/javascript/
JSON is a pretty interesting application of object literals. I'm wondering if it could be exploited to do something like a crossbrowser "Data island". Maybe this is a silly idea with XmlHttp just a few keystrokes away nowdays.