Just wrote my first Greasemonkey script to help out an old friend. The script (http://userscripts.org/scripts/show/35685) adds links to BBC Radio schedules (e.g. http://www.bbc.co.uk/radio7/programmes/schedules) where you can download the Realplayer version of a show that's on IPlayer.
I was quite impressed by how easy putting together a Greasemonkey script was. Unfortunately there seems to be a limit to how many GM_xmlhttpRequest functions you can fire off (seems to be about 5). As I need to hit a second page to find each RealPlayer link, this limit means I can't get the links for all shows on a schedule when the page loads.