ytlyrics --- https://yt-lyrics.appspot.com/
YT-Lyrics bookmarklet --- https://yt-lyrics.appspot.com/
Second version of the YTLyrics bookmarklet.
This time I involved App Engine and python (plus obviously Javascript) because of new restriction of the webkit browser (improving XSS security) broke the old bookmarklet based on 100% Javascript and Yahoo's YQL, and I couldn't figure out how to serve the lyrics without using a backend of mine.
I have a very basic knowledge of python, but at the time i developed the bookmarklet the PHP version of App Engine was not out yet (now it is :) ), and I really needed the Google TLS certificate to avoid the XSS protection nuisance.