Buildout.python_libevent is a project mainly written in Python, it's free.
Buildout recipe for python-libevent
This buildout recipe can be used to build the python-libevent module and link libevent itself statically.
Add the following section to your buildout script::
[python-libevent]
recipe = buildout.python_libevent
eggs = python-libevent
libevent = http://sourceforge.net/projects/levent/files/libevent/libevent-2.0/libevent-2.0.13-stable.tar.gz"libevent" points to a released tarball of libevent which will be downloaded and compiled using the regular "configure && make" and will be used to build python-libevent.