Haskell

Haskell is a purely functional programming language. It is named after Haskell Brooks Curry, a U.S. mathematician who contributed a lot to logic. Haskell is based on lambda calculus and uses the Greek letter lambda as its logo. The main implementations are the Glasgow Haskell Compiler (GHC), and Hugs, a Haskell interpreter.
Examples.
The following is an example Hello World program in Haskell:
module Main where
main :: IO ()
main = putStrLn "Hello, World!"
One way to create an infinite list of Fibonacci numbers is this:
fib n = fibs !! n
 where fibs = 0 : 1 : zipWith (+) fibs (tail fibs)
Influence.
Haskell was influenced by many earlier programming languages. These were Clean, FP, Gofer, Hope and Hope+, Id, ISWIM, KRC, Lisp, Miranda, ML and Standard ML, Orwell, SASL, SISAL, and Scheme.
Haskell itself has influenced many later programming languages, such as Agda, Bluespec, C++11/Concepts, C#/LINQ, Cayenne, Clean, Clojure, CoffeeScript, Curry, F#, Isabelle, Java/Generics, Mercury, Perl 6, Python, Scala, Visual Basic 9.0.