OK, they're not folk or blues, but very funny, campy, satirical duo.
Saw them last night in Guildford UK, if you like that sort of thing don't miss their current tour. Among the topics dealt with in their gleefully un-PC fashion were:
Robin Cook
George Bush
Gypsies
Guantanamo
Lesbians ("Ladies who munch")
Spaniards
Royal Dogs
Joan Rivers/face lifts
Bishop of Reading/Leviticus
Nigella Lawson-Saatchi
Jacko
Cornwall
LOTR
Shopping
...and others I can't recall at the moment!
and of course we all joined in the finale singing the Indian Restaurant menu to the tune of Puccini's "One Fine Day".

RtS