First off, stumbled across springshare which is web 2.0 apps for libraries. I guess it's about time someone created library specific applications to sell back to the library community. Of course, for some libraries with small budgets or suffering budget woes, opensource products or free stuff (del.icio.us) may be the only option. I'm not sure my library could afford to purchase this, if we were so inclined. It would be interesting to see how it stacks up against opensource stuff, though.
Out of microsoft labs, 3D modeling stuff. You can play with it for free online here
Artists can join the one million masterpiece. I seem to remember a similar project involving collaborative advertisements...
Anyone can create a virtual slideshow for use on a website, blog, etc. If you flickr you already have a similar tool available, but still kind of neat.
...and under possibly the most useful of all of these, powcne, a way to virtually share about anything electronically.