stack based languages

Hello, i am interested in learning a stack oriented language, so i started learning Forth. (from http://www.amresearch.com/starting_forth/)
Some alternatives i heard of are cat and factor.

What is best to learn from those? And suggest a good tutorial

>>5
I don't think so, honestly.

You can do funky tricks with them, since they're pretty much Lisp minus the parens, but the readability leaves a lot to be desired.