Diego Inácio has created several geometry tools for Houdini, using Python.
Houdini Connect: RISE FX
Andreas Giesen and Simon Ohler talk to SideFX about Houdini and the RISE Visual Effects Studio pipeline.
Tea and Cookies in Houdini - Tutorial
Tea and Cookies in Houdini is a two part commercial tutorial in Houdini, going through all the steps of the scene's creation.
Jayden Paterson - Houdini FX Reel 2014
Jayden Peterson has posted a reel showcasing his Houdini FX work.