
Happiness, Giving, Positive 'mocks' of revolutionist-advertising, Imagination... these are the advertisements that I looked for. If it had a specific color theme, I was more inclined to go with it.
For the Red M&M pic, they do a mock-up of old posters of revolutions (or at least mocking foreign politics/war posters).

The Lego "Imagination" idea was too good to pass up. I loved those things as a kid, and they were the medium for lots of my imagination. This add really plays up on that idea (though I wouldn't take three square blocks and call it a T-Rex...but the exaggeration only helps in explaining)

And finally, I can't forget this one between the two dogs. I don't really have too much to say about this, aside from 1) either the dogs are ridiculously trained, or it's photoshopped, and 2) the obvious act of them 'partnering up' could be represented in numerous things, with its broad approach at something positive in regards to teamwork, or helping others out.