However I reckon I have a decent general knowledge and I was listening to the radio and someone mentioned a Shakespeare play called King John. Now my brain whirred away and went "you what?". Now I've never heard of a Shakespeare play called King John.
So a quick scan of the internet shows there was a play called King John. The wikipedia entry says:
In the Victorian era, King John was one of Shakespeare's most frequently staged plays, in part because its spectacle and pageantry were congenial to Victorian audiences. King John, however, has decreased in popularity: it is now one of Shakespeare's least-known plays and stagings of it are very rare.
I then went and looked at the list of Shakespeare plays and found four others I had never heard of. Anyone heard of "Pericles, Prince of Tyre", "The Two Noble Kinsmen" or "Cymbeline". And blow me he wrote a play called Henry VIII!!
Also I didn't realise that some of his plays may have been collaborations (and no I'm talking Bacon). Admittedly not the "major" plays.