My mother is a music teacher. In 2003, looking for educational software we came across GCompris, and she liked it a lot. At the time she tested it thoroughly, and spotted a typo. We submitted a patch, and were having fun when it was applied upstream.
Recently she asked me how she could "give GCompris to a friend". I gave this problem some thought, and came to the conclusion that the best way might be to use a USB stick with some live distro with GCompris.
I bought a 2 GB USB stick with the latest Knoppix pre-installed for less than 10 Euro. With the included package manager I installed GCompris. I noticed that its optional dependencies (tuxpaint, gnucap and gnuchess) didn't get pulled in, and installed them as well.
Voilà, GCompris on a USB stick. Works perfectly. :)