a collection of some not-so-popular language that I have encountered
Teach yourself programming in Ten years(Peter Norvig: Author of AIMA, and director of search quality at Google, Inc):
http://www.norvig.com/21-days.html
Python:
Lisp:
Scheme( dialect of Lisp)
Prolog:(Logical Programming)
ML:
Haskell
(interestingly it's carrying the gene of other functional and semi-functional language, and survived at an academic level):