The big news in the MySQL and the open source database worlds right now is Drizzle.
This is the "secret project" that I have occationally mentioned here. For the past few weeks, when I was done giving my PS client their daily 8 hours, I would flip VMs and start hacking on Drizzle, focusing mainly on the plugin system. I've ripped out a lot of junk and useless code, changed the plugin interface structures, converted UDFs into plugins, and am currently working on making logging and authentication into plugins.
The bzr tree is rapidly changing, and getting leaner, cleaner, better, and faster, with each passing day. The email list and the freenode IRC channel have been clear and focused.
It's been very exciting.