Forth is a charming little language, and I highly recommend spending a few evenings implementing one on the processor of your choice. You'll be astonished at how much functionality will fit in just a few kilobytes. FORTH will teach you no-foolin' hard core pragmatism, and a few dirty tricks that will make you smile.
(That said, I don't like FORTH much at all. The amount of stack-thinking is just agony).
(That said, I don't like FORTH much at all. The amount of stack-thinking is just agony).