ibelieveinadv.com is a blog which comments on any eye-catching, or effective advertising from around the world. The picture above is one of my favourites - it's a bus shelter with a clear panel into which any rubbish collected from in and around the shelter in the past week is put. What an effective way of showing people exactly how rubbish (ha!) they are being by littering.
This is a great resource for inspiration on how other countries and advertising agencies are approaching advertising campaigns across different media. Well worth a look.