MIT has Scratch on Linux. Check the site for more details. It is interesting to note that Scratch runs on Squeak.
Debian / Ubuntu Package
You can download the latest Scratch package for Ubuntu from our Download page. The source code for this package is hosted on Assembla, as is the list of bugs. If you’d like to help improve the scratch package for Linux, e-mail us directly. Here is a link to the Scratch Team page on Launchpad.
Linux Camera Plugin
The camera Plug-in for Scratch on Linux is designed to work out of the box with a wide range of USB webcams. If you are having problems, see this page for help troubleshooting.
Scratch and Squeak
Scratch runs on Squeak, which is written in smalltalk, one of the first object oriented languages. So Scratch is an ‘image’ that runs in a squeak virtual machine built for a particular OS. You can find out more about Squeak and Scratch on our Source Code page.