I've been talking about sponsorship lately.
The use of celebrities isn't really sponsorship - it's more endorsement - but it kinda falls under the same roof. Ultimately it's about using the vehicle of a celebrity or an event to drive the equity and the sales of a brand.
I like this ad for Nike, featuring supergrunter Maria Sharapova. It really captures the whole "Just Do It" positioning, probably better than any other Nike ad I've seen.
I'm looking for an ad which uses an endorser but has missed the mark somewhat. Can't find one...that will have to wait for another day.
In the meantime, this sketch involving turtles from Shaun Micallef will have to do.