A 1h20m presentation on Google's new communication service/framework, Wave. The video is a must-watch as it really is the only way to even attempt to grok this neat product, but even with the visual it still is a bit much to take in all at once. (See also the follow-up press event.)
I can see Wave being hugely popular for those currently reliant on the Google ecosystem, but for others it may not be as painless a sale (if only because it's not terribly easy to wrap your head around).
It's a lofty goal to reinvent separately any of email, instant messaging, or project management, let alone simultaneously, but just because the aspiration is ambitious doesn't mean it's impossible, and we've seen Google change the way we think about entrenched technologies many times before (read: search, Gmail, Google Maps, etc.).