Re: I'll raise you
Even more obscure than any of these, however, was NNAPL*.
It has no data types beyond INT and (iirc) STR and requires you to define your data structures by the number of bytes they will require - /and/ you have to remember to add two bytes to the total for each for a CRLF at the end of each of them.
It's entirely possible to add 144 to 'last Tuesday'.
Try working out wtf I was doing when I wrote /that/ code - even I don't have a clue what it's doing ;)
* Neural Net Application Programming Language.