This is a sweet 4/20 show from a pretty righteous band, and you can stream the show or click on an individual song rather than downloading them, so it's good for listening to at work. Definitely worth listening to. http://www.archive.org/details/pgroove2005-04-20.flac16

Here's another 4/20 show from String Cheese, so take a look at this if you so desire.
http://www.archive.org/details/sci2001-04-20.ew.shnf