Qimo is a (discontinued) desktop operating system designed for kids. Based on the open source Ubuntu Linux desktop, Qimo comes pre-installed with educational games for children aged 3 and up.
Qimo's interface has been designed to be intuitive and easy to use, providing large icons for all installed games, so that even the youngest users have no trouble selecting the activity they want.
Version 1.0 of Qimo was released on 2009-02-18, according to distrowatch.com
Their website: http://www.qimo4kids.com/download/