I've been a user of Partychat for a few years now, both in its previous hosted-on-a-server-in-someone's-living-room implementation and in its current App Engine-based one.

Needing a fun side project (and having a few itches that I needed scratches), I've spent quite a few evenings over the past month making changes to the source code. So far I've managed to:

• Make the homepage friendlier (and slightly prettier), especially the room creation form.
• Improve web-based room management (building on what David started), so that you can join, leave, or request an invitation from the room's web page (here's a sample room for the current developers).
• Prettify the plusplusbot display in the web UI.
• Add a /share command that makes it easy to share URLs and give some context.
• Clean up some data layer issues and fix some inconsistencies.
• And of course, quite a few bug fixes (nothing like scanning the AppEngine logs looking for NPEs).

Like with all fun side-projects projects, they can also turn not fun once usage picks up. For example, yesterday a user invited room A as a member of room B, and vice-versa. As an unintentional side-effect of a change that I made to make the setup process more user-friendly, it became very easy to set off an infinite loop of messages. By the time I realized what was going on, we'd run out of App Engine bandwidth quota. Thankfully after some budget rejiggering and a some quick code change all was well. Similarly, a couple of weeks ago we had CPU usage issues (though optimizing that away was still fun).

It seems like chat is gaining in trendyness, with HipChat launching recently (presumably to challenge the incumbent Campfire) and Brizzly/Thing Labs's Picnics happening. Partychat will probably remain a hobby/fit-within-AppEngine-free-quota sort of project indefinitely, but it's been fun polishing it (and of coure, there's still quite a few things left to fix).

And of course, if you need IRC 2.0 a persistent chat room you should give it a try.