What the hell is this Google Wave thing? - 2 Minutes will explain it all.
So what is this Google Wave thing?
I get that Google Wave is an attempt to re-invent a modernized version of email. But its mashup of email, documents, and social networking is kinda hard to get your head around. For me at least, this video helped.
And if you still don't know WTF the big deal is, take a look at Lifehacker's excellent in-depth review.