Recently, rather than listening to music CDs on the commute to work, I've decided to pop on a couple of episodes of audio comedy instead, namely The Mighty Boosh (which I borrowed off my girlfriend), Flight Of The Conchords and The Hitchhikers Guide To The Galaxy. These choices were based on the fact that I liked their incarnations in other forms of media but as I was listening to them I got to thinking that I was probably missing out on a vast resource of brilliant comedy that I've never heard of before. Scripted comedy (or any other form of comedy really) is rarely, if ever, broadcast on the radio here so it was something that I'd never been exposed to or considered giving a chance until it began to get more and more coverage on this site.
So basically, I was wondering if anyone could recommend some of the best radio comedies for me, both past and present. I would prefer ones that have not been made into TV series (due to the fact that like the 3 I mentioned above they would just contain material that I'm already familiar with) or ones that are just the audio versions of TV series (e.g. The Smoking Room, Yes Minister).