Juxt Interactive has recently created an advertainment website for Dannon's Spring Water. The site is definitely very well designed, with nice animations and a good navigation interface.
What I really liked are the "loader games" to play while you wait for the content to load. An excellent idea for any advertainment style site packed with heavy content. People expect the site to be entertaining, so they don't get bored while waiting for the entertainment to be delivered.
On the contrary I believe the advergame is not as good and sticky as it could have been: you are asked to retouch a photo by spray water in the person's face, it would have been so cool if you could actually upload the photo of a friend and play with it instead.