Type Ibn supernovae form a subclass of (likely) core-collapse supernova explosions whose ejecta interact with He-rich (and, usually, H-poor) circumstellar material. The prototype of this class, SN 2006jc, is one of the best interacting SNe studied so far, with constraining information of the progenitor's system. However, many other supernovae Ibn have been discovered in the last decade, showing an unexpected variety of observational properties. This talk will review our current knowledge on this supernova class.