MySQL Labs
Who remembers snaps? This is the place to go, when you wanted nightly source code snapshots of stuff that comes out of MySQL AbSun Microsystems build systems, that is related to the MySQL product line. There you can get all the snapshots for GA releases, as well as archives; (albeit not very up-to-date). 
Anyway, its good to know now there is a focus, just for server snapshots, available at MySQL Labs. These are testing builds, that come out directly from pushbuild (the build system). Its not for production use, but what’s really useful is the fact that there’s also a recommendation to use the MySQL Sandbox, written by Giuseppe Maxia. Today, I see builds for 5.1 and 5.1 with GIS extensions.
In due time, I expect 5.4 and 6.0 builds to make its way. This should help QA a lot more as well, as people start playing with daily builds, and finding bugs. In case you’re wondering why there have been no updates in a couple weeks, just hang in there. Its currently manually pushed, but will soon be done automatically via cron(8).
I thought that 6.0 was done? What are we to call the releases that follow 5.4?
6.0 itself is done, but there are some interesting features that you’ll see show up – things like online backup, batched key access, etc. So, in that sense, you’ll look at it like the 5.1 GIS snapshots.
Good question, what do we call what comes after MySQL 5.4? MySQL Next? Mmrm.