Drizzle, Percona and MariaDB

There are several MySQL forks out there. The 3 most popular ones can be setup from repositories in Ubuntu:

Drizzle: it's a complete fork, the guys at drizzle.org want to build a new database using MySQL only as a starting point. In their own words: "The Drizzle team has removed non-essential code, has re-factored the remaining code, and has converted the code to modern C++ and modern libraries.". And the best thing is that it's about to release its first GA binaries.
• MariaDB: Founded by Michael Monty Widenius, who is also the original author of MySQL, MariaDB is a drop in replacement for MySQL. They provide enhancements over the regular MySQL database and regularly sync up with the official MySQL tree. Finally, MariaDB ships with the XtraDB, the DB engine derived from InnoDB and developed by Percona. Visit mariadb.org for more information.
• Percona: Percona Server is the contender that has been there for the longest time. It's also a drop in replacement for MySQL and they have a DB engine of their own which they claim is faster than InnoDB: XtraDB. Here is the Percona Server page.

Repository and package indexes for those 3 MySQL forks are available by following the links below.

Happy SQL!