Felt like a real badass in middle school when I made my first .bat script that would recursively open itself. Took only two words. Four if you wanted exponential recursion rather than linear. And I came up with it by myself.

Cheesiest thing ever, but I really loved freaking people out by opening it and just watch windows grind to a halt as it would run out of ram opening thousands of terminal windows. Hell, it still gives me a kick today when I show it to people the first time :D