Diego Inácio has created several geometry tools for Houdini, using Python.
Houdini 14 Release
Side Effects Software have announced the release of Houdini 14, with sand and crowd tools.
Side Effects Software have announced the release of Houdini Indie for independent animators and game makers.
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.