Some APL notes:
-It comes from math. The weird Greek symbols are favored by mathematicians writing formulas.
-Its author later wrote J, and APL users mostly switched to J.
-APL specializes in vectors: sorting, searching, merging, etc. When you step outside that problem domain, APL can be more trouble than help.
-Morgan Stanley wrote the A+ implementation of APL and offers it free. Vector math is useful in financial computing.
-The IOCCC 1989-robison program is a pico APL interpreter. No loops, but it does have functions and "indirection".
-Most full implementations have an interactive environment supporting individual function changes and fast development.
-dmoz has a category:
http://dmoz.org/Computers/Programming/Languages/APL