The first time you run a command with "sudo" in Ubuntu, you are asked for a password but after running one more command with "sudo" (after a short while), you are not prompted for a password again. That's because "sudo" has a default password time-out (I'm not sure how long it takes to expire though).
I recently found a fun feature available within the sudo program, that got over 500 Digs today!! that will insult you when you do the wrong thing such as enter your password incorrectly. I’ll tell you how you can activate the feature for a few laughs and also give a few examples of what insults you might get.