Alec mentioned Scratch and quickly demo-ed it on Raspberry Pi in his talk at the meeting.

At LCA they mentioned that they're interested in optimizing Squeak, the underlying Smalltalk implementation for ARM for speeding up scratch on the Raspberry PI. The  bug report is
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=77&t=12522
A google summer of code link for bootstrapping the Squeak JIT for ARM, I think all in Smalltalk.
http://gsoc2012.esug.org/projects/arm-jitter
Squeak underlies Etoys too.

Looking at the Scratch website http://scratch.mit.edu/help/faq/ , the new Scratch 2.0 version will run in browsers with Adobe Flash 10.2. Will that run on the Pi? I'd guess not.

http://byob.berkeley.edu/ Snap! (Build Your Own Blocks) 4.0 derived from Scratch has also moved off Squeak, but is implemented in Javascript. It ran for me in Firefox 22.0 on Ubuntu  and Chrome and loaded at least in a colleagues Android phone.
If it works ok in the browser on Raspberry Pi and Android tablets it would be good to demo at Software Freedom Day.

Anyone want to give Snap! a try on a Pi or a tablet?