One of Forth's strengths is its ultra-simple syntax. If you thought Lisp had little syntax, think again. Forth is just tokens and whitespace. You can write a compiler than can compile itself in a few screenfuls of Forth (and I'm not talking about eval).

Forth is obscure but beautiful. It's reflective, meaning you can write code that writes code (macros). Also like Lisp, you can easily roll your own control structures or add an OOP interface. But it does lack good libraries and a decent-sized user base.

One of the most interesting things, to me, was the built-in disassembler: if you ask 'how is this word defined', and it's not defined in the current environment, it'll go disassemble the binary and show you that.

Pretty insane, if you think about having to write software to interface with old / undocumented / closed source libraries.

: accgen create , does tuck +! @ ;

From comp.lang.forth: http://groups.google.com/group/comp.lang.forth/msg/f06370fed978abff?dmode=source