Raspbian
Raspbian is a version of Debian for the Raspberry Pi. It is possible to install sugar on Raspbian.
Sugarizer
Sugarizer is a HTML5 version of Sugar. It has a basic journal and full web activity support.
You can configure Sugarizer to auto-start by setting your ~/.xinitrc to:
epiphany server.sugarizer.org
(Note: there are a few issues with the browser icons... but sugarizer works well)
Alternatively, you can download the Sugarizer client zip and have it locally on your pi.
Using APT-GET
A old version of Sugar (Sugar 0.96) can be found in the Raspbian repositories. You can install it with:
sudo apt-get install sucrose-0.96
Then set sugar as your desktop environment by opening/creating ~/.xinitrc. Set this file to:
sugar-emulator -f
Now whenever you startx you will have the delights of Sugar 0.96.
If you want to use activities other than Turtle Blocks or Pippy, you will need Browse to access the ASLO. You can install Browse by running:
wget http://download.sugarlabs.org/activities/4024/browse-129.1.xo sugar-install-bundle browse-129.1.xo