Development Team/Jhbuild
One of the easiest ways to install Sugar is to use Sugar-jhbuild.
Sugar-jhbuild will automatically download the latest of sugar's dependencies as well as sugar itself directly from their source repositories, rather than relying on source packages that may have become stale. Below are generic instructions on how to use sugar-jhbuild to get up and running with Sugar.
Sugar-jhbuild does have its own dependencies. For OS and distribution-specific information, such as what these dependencies may be, see the Installing Sugar category and look for your OS.
Checkout sugar-jhbuild
git clone git://dev.laptop.org/sugar-jhbuild
Build sugar and it's dependencies
cd sugar-jhbuild ./sugar-jhbuild build
Run Sugar
./sugar-jhbuild run
Notes
Sugar-jhbuild is still in early development. In particular, dependencies detection will be improved. It needs a lot of testing, so give it a try and report issues!