MySQL 5
Two days ago, I got MySQL 5 running. True, it is only alpha, but let me tell you, views are awesome. Triggers are kind of cool. Stored procedures are there too. Anyway, right now my desktop has both 4.1 and 5-alpha running :-D Maybe I should try to do something fun, like installing yet another mediawiki, or changing some settings and test the PHP-based chat system I and a friend of mine wrote about a year ago.