I've been rather underwhelmed with the selection so far. I happened to be poking around sourceforge and found these:
Colors is an entertaining educational game designed for children ages 0-2. If a character is pressed a sound will be played and the screen will change colors. Optionally, characters can be displayed and heard instead of sounds. Requires SDL
Childsplay is a 'suite' of educational games for young children. It's written in Python and uses the SDL-libraries to make it more games-like then, for instance, gcompris. The aim is to be educational and at the same time be fun to play.
I've tried out Colors and it seemed pretty appropriate (needed to edit the makefile and a hard coded path in the source to build a slackware package for it, however). I have not yet had an opportunity to try out Childsplay.