Rating: Incredibly easy.
- Open Synaptic (System > Administration > Synaptic package manager)
- Search for "sugar"
- Install sugar, sugar-emulator, sugar-activities, and anything else you want
Thanks to Jani Monoses, who made the .deb packages and got them included in the Ubuntu sources!
Rating: Pretty darn easy.
Open up a terminal and add to your sources list...
$ sudo -s # echo "deb http://ppa.launchpad.net/jani/ubuntu gutsy main" > /etc/apt/sources.list.d/sugar.list # apt-get update
Then apt-get as root.
# apt-get install sugar sugar-emulator sugar-activities
Rating: Mildly painful, but probably getting better soon.
Rating: Painless, but less flexible and sometimes slow.
Use the QEMU all-in-one zip-file installer - this easy install package was created by Mitra, a high school student from Illinois.
 OS X
Emulation is currently the only sane way to go.