At the moment I have two that I say randomly on a fairly regular basis, one is from a TV show and one from an advert.
First up we have 'Skills!' which me and my sister got from Morgana Robinson's 'impersonation' of Fearne Cotton. She says it quite early in to the video.
And the other is from a BT advert which brings us 'Rocking from an early age'. It is said right near the end of the advert... but it only lasts 41 seconds.