Strictly speaking it's Yahoo property and I shouldn't. But if you just want to read some Lisp code you could look at the source of HN: http://www.arclanguage.org/install
Do you think they'd be averse to letting you publish the code they've since re-implemented?
On a more personal note, if you'd look at ViaWeb code with hindsight, would you still believe it was well-architected and exactly as it would have been if you were to write it today? (Not considering the evolution of web technologies in general)
I don't know how good the code is. I haven't looked at it since I quit. And I don't want to look at it because if I find it I'll want to try to get it running, which will end up making me port it to Arc, and I don't have time to jump down that wormhole right now.