I was browsing through Core77 magazine, and found the London Design Festival 2008 image gallery, which I think had many fantastic examples of innovative, engaging and effective design. I especially enjoyed Designersblock, at the Piazza in Covent Garden, with three floors of industrial, communication, fashion, audio and visual design.
One of my favorites was an italian designer duo that would show you how to make gnocchi. The project in itself was in a way, socially engaged, because it would allow the participant to socialise with others. There were numerous examples of effective design as well.
I encourage those who couldn't attend to browse through the gallery. There are several great examples of good design, with a social conscience, like for example, the korean designers exhibition, in Designersblock.