Things are moving both slowly and quickly. But I'm having fun. I'm now at the point that it's not just an activitystreams library; it also ships with a demo ActivityPub implementation that's starting to work.

Activities can be submitted through the API endpoint, though the oauth bearer token check isn't handled yet (probably done today)
Basic content rendering in HTML works, using a generic methods system in combination with sxml to pull down the right templates. sxml is great.
There's a mini REPL driven client
The asobj abstraction system is a dream to work with

Things are nearly demo'able. What I need to do still:

A few more things renderable
Handle collections properly
Finish implementing and make use of cookies (Guile doesn't ship with cookie support out of the box, but I have it nearly done) and do cookie signing as a kind of web based session
Web based UI for submitting new activities, interacting with existing ones

There's a lot to do still, but it's finally at the point where things are looking real. I'm also further along than I was with Pydraulics, and am enjoying working on it a lot more.