Argh! and its extended form Aargh! is another minimalist language following on the ones I have already mentioned.
While this one, released by Sascha Wilde, seems just as odd as the others at the outset - if you look closely at the operations then you will see that it should be possible to write some quite useful things in Aargh!
What I particularly like about this one is its visual nature, and the way that execution processes around the program in a 2D form.