Go

http://golang.org/

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.

Example:

package main

import "fmt"

// fib returns a function that returns
// successive Fibonacci numbers.
func fib() func() int {
	a, b := 0, 1
	return func() int {
		a, b = b, a+b
		return a
	}
}

func main() {
	f := fib()
	// Function calls are evaluated left-to-right.
	fmt.Println(f(), f(), f(), f(), f())
}

// Concurrent computation of pi.
// See http://goo.gl/ZuTZM.
//
// This demonstrates Go's ability to handle
// large numbers of concurrent processes.
// It is an unreasonable way to calculate pi.
package main

import (
	"fmt"
	"math"
)

func main() {
	fmt.Println(pi(5000))
}

// pi launches n goroutines to compute an
// approximation of pi.
func pi(n int) float64 {
	ch := make(chan float64)
	for k := 0; k <= n; k++ {
		go term(ch, float64(k))
	}
	f := 0.0
	for k := 0; k <= n; k++ {
		f += <-ch
	}
	return f
}

func term(ch chan float64, k float64) {
	ch <- 4 * math.Pow(-1, k) / (2*k + 1)
}