CoffeeScript source maps
ryanflorence.com
ryanflorence.com
https://github.com/Constellation/escodegen
Note: I do not want it to seem like I want to take anything away from Michael Ficarra and the new CoffeeScript compiler. He also wrote the code to integrate source maps with ESCodeGen, but it is something that many projects will be able to take advantage of, not just CoffeeScript.
In other source map news, if anyone hasn't seen it yet, UglifyJS v2 now supports source maps: http://lisperator.net/blog/uglifyjs-v2-news/
Source map support is on the way for Firefox's debugger as well: https://bugzilla.mozilla.org/show_bug.cgi?id=771597
It's no issue for me personally, but it helps smooth over resistance to CoffeeScript.