APL was the first language I learned - I had a very interesting and forward looking Engineering Professor who taught us how to solve complex systems of equations using APL. I loved it, and am sorry that I don't use it anymore.
IBM APL2 was the 3rd or so language I learned. At Merrill, I remember workspaces with tens of thousands of LoC, possibly over 100K. Also we used to have "each" contests and obscurified APL contests, where nobody could read anybody else's code
