You need to listen to the first episode to know who everyone is (and why they are what they are), and then it's great - the dark lord and his sidekick reminds me of Time Bandits! Fantastically funny (and the 2nd series on the radio at the moment is just as good). You have to get this!
Another great series - embarrassingly, the emergency procedures made me laugh out loud whilst listening with headphones - I got very strange looks as I continued to snigger and wipe my eyes. Highly recommended
They just make me laugh every time I hear them. Truly stupid and very funny.