A Midsummer Night's Dream
From Tardis Wiki, the free Doctor Who reference
A Midsummer Night's Dream was a play by William Shakespeare. The Fourth Doctor called it the "one with the ass's head and the chink in the wall". He suggested that he could play Thisbe and Romana II Pyramus — or "the other way round". K9 Mark II he imagined could play the part of the Lion, but K9 seemed unenthusiastic.
Romana II once forewent a performance of the play in order to see the comparatively "more useful … and much funnier" The Hitchhiker's Guide to the Galaxy. (PROSE: A Midsummer's Nightmare)