I don't know much about their website changes, but yes, it still works.
A shorter version of the script:
mplayer `youtube-dl -g "$*"`
To use it, save it as yt.sh, make it executable by "sudo chmod u+rwx", then
type ./yt.sh "http://www.youtube.com/watch?v=xxxxxxxxxx".
To call it as an installed program, copy it to /usr/bin without any file
extension, only "yt", then call it by "yt" and the URL quoted.
Alternatively, you can type this as a command in the terminal and replace $*
with the URL. To view another video, type the up arrow to bring the last
command and replace the URL again.
I ommitted &> /dev/null. What it means is "move all output to /dev/null". You
wouldn't get any text on the terminal while watching the video.
Update about cclive/clive: They removed support for playing on-the-fly. You
can use get-flash-videos instead and call it get_flash_videos -p "URL". It
will, however, save the file locally so you have to delete it if you don't
want it.