One of the things that I've argued over the past few months is that for ads to work, they have to be compelling enough for people to actually want to watch them. One of the ways to do this has been to combine the advertising material with the actual content, so that in effect the content IS the advertising. Another way is the make the ads interactive, and to get people to engage with them in one way or another. It used to be that this was done simply through contests, but advertisers are getting more interesting.
A recent example is the latest commercial for Killzone 2, a game for the PlayStation 3. As the lads down at Citizen Game point out, "Sony is actually going to release a *playable* version of this commercial in March where you can control the camera and the speed of playback while listening to director commentary."
It is a great way of getting people to actually interact with the ad, rather than passively let it wash over them, while demonstrating the capabilities of the game as well.