I saw Shakespeare by the frame, and looked on the bottom of the mug: Wedgwood, honey.
I've been enjoying tea and coffee in this mug all the more for the mug. I decided to peek at eBay and see if I could find more. 1964, Stratford-Upon-Avon Advisory Council. Crap. I've seen the last of the fifty cent versions of these: there's a buy it now on eBay for $55.00. There's also a buy it now version for $21.96, but it's in England, and I'll bet the postage makes it closer to the $55 version.
Turns out this was one of a series of five lithographed mugs designed by Wedgwood artist Victor Skellern to commemorate the 400th anniversary of the birth of Shakespeare.
Or maybe I should sell it...?