Diego Inácio has created several geometry tools for Houdini, using Python.
Making of Ambition with Houdini
Platige Image go behind the scenes on their Ambition short film and how they used Houdini for the effects.
Arnold for Houdini
Solid Angle have released the first public release of their Arnold renderer for Houdini.
Side Effects Software have announced the release of Houdini Indie for independent animators and game makers.