This post is really just here to have a bunch of syntax highlighting stuff in one place. IGNORE ME! (unless you just want to see some pretty colored code blocks, in which case read on).

JavaScript

function getRandomNumber() {
    return 4; // chosen by fair dice roll.
              // guaranteed to be random.
}

Scala

case class Person(name: String, age: Int)

def absoluteValue(n: Int): Int =
  if (n < 0) -n else n

val hux = "hux"
def mux = "mux"
def qux: String = "qux"

type ξ[A] = (A, A)

trait Hist { lhs =>
  def (rhs: Hist): Hist
}

def gsum[A: Ring](as: Seq[A]): A =
  as.foldLeft(Ring[A].zero)(_ + _)

sealed trait Compass
case object North extends Compass
case object South extends Compass
case object East extends Compass
case object West extends Compass

trait Cake {
  type T;
  val things: Seq[T]

  abstract class Spindler

  def spindle(s: Spindler, ts: Seq[T], reversed: Boolean = false): Seq[T]
}

val colors = Map(
  "red" -> 0xFF0000,
  "turquoise" -> 0x00FFFF,
  "black" -> 0x000000,
  "orange" -> 0xFF8040,
  "brown" -> 0x804000)

lazy val ns = for {
  x <- 0 until 100
  y <- 0 until 100
} yield (x + y) * 33.33

CoffeeScript

class Animal
  ### Intellegent design ###
  getDNA: ->
    print 'sequencing...'
    while true
      sleep 1

class Monkey extends Animal
  speak: ->
    print 'ah ah ah'

class Human extends Monkey
  speak: ->
    print ['yolo' unless i % 3] + ['swag' unless i % 5] or i for i in [1..100]

C

#include <stdio.h>

int main(void)
{
  printf("Hello world\n");
  return 0;
}

C++

#include <iostream>

int main()
{
  std::cout << "Hello World!" << std::endl;
  return 0;
}

C-sharp

class ExampleClass
{
    static void Main()
    {
        System.Console.WriteLine("Hello, world!");
    }
}

Erlang

io:format("~s~n", ["hello, world"])

Go

package main

import "fmt"

func main() {
   fmt.Println("Hello World!")
}

Java

public class HelloWorld {
   public static void main(String[] args) {
       System.out.println("Hello world!");
   }
}

ObjectiveC

#import <stdio.h>

int main(void)
{
    printf("Hello, World!\n");
    return 0;
}

PHP

<?php echo 'Hello, world'; ?>

Python

print("Hello World")

Ruby

puts "Hello world!"