DL-Learner is a tool for learning concepts in Description Logics (DLs) from user-provided examples. Equivalently, it can be used to learn classes in OWL ontologies from selected objects.
As of August 2014, the source code management of DL-Learner has moved to Github: https://github.com/AKSW/DL-Learner
Please use this for the latest code and issue tracking and the website (http://dl-learner.org) for general information.
Free, very quick, easy to use and rock solid. A top quality application.