Mildly amusing Facebook javascript prank. Run this code in the javascript console off someone who has Facebook running in their browser all the time. Sit back and watch the headscratching and frustration commence.

gistfile1.js

function FBNotificationsPrank(){
    document.getElementById('fbNotificationsJewel').className = document.getElementById('fbNotificationsJewel').className + " hasNew";
    document.getElementById('notificationsCountValue').innerHTML = 1;
    document.title = "(1) Facebook";
    setTimeout(FBNotificationsPrank, 10000);
}
FBNotificationsPrank();