We finished the landing page — before that, Brick didn't even have a landing page — and put it out on HN.
This brought us about ~1000 signups, four paying users the same day, and four more during the next week.
The best things about publishing Brick on Hacker News were:
realizing that Brick is actually good enough already and we don't have to worry about it seeming amateur or "not done yet",
and noticing that we need to make Brick much more immediately appealing — a huge percentage of the 1000 users ended up abandoning Brick without giving it a try, and so we needed to entice them to spend a bit more time with it.