Pash - An Open Source reimplementation of PowerShell for Mono
PowerShell is fantastic, and we aim to make it available on Mac and Linux with Pash.
Igor Moochnick made the first release of Pash in 2008, and then development stalled for the next 4 years. In August 2012 Jay Bazuzi picked up the mantle, and development has been chugging along on GitHub. Come watch, or join in the fun!