Compiling from Source

Git

git clone git://github.com/eventmachine/eventmachine.git
cd eventmachine
rake build

irb -Ilib:ext

SVN

If you prefer to not use the gem but to get the 'latest svn HEAD version'...

svn co http://rubyeventmachine.com/svn/ eventmachine
cd eventmachine
rake build

irb -Ilib:ext

Viola. latest and greatest.