Microsoft To-Do - Task management tool
DejaGnu - DejaGnu is a framework for testing other programs.
Gone - An ephemeral to-do list
Expect - Expect is a tool for automating interactive applications such as telnet, ftp, passwd, fsck, rlogin...
KosmoTime - The to do list with super powers
Check - Check is a unit testing framework for C, which runs on environments such as GNU/Linux, GNU/Hurd, BSD, and Mac OSX.