Modelio - Modelio is an open source modeling tool supporting natively UML, BPMN and model exchange with XMI.
Detective Game - Who is the robot and who is the human?
Diagramo - Diagramo is an online flowchart software - diagrams (create, edit and share)
You Dunnit - Personalised murder mystery game builder
UML Designer - UML Designer provides a set of common diagrams to work with UML 2.5 models.
Catphish - A game to play Sherlock and find out who's lying