Obtaining the library source from Mercurial

From CEGUI Wiki - Crazy Eddie's Gui System for Games (Open Source)

To obtain a copy of the code from mercurial, you might use the following commands (or thier equivalent, if you use a GUI based mercurial client)

hg clone http://crayzedsgui.hg.sourceforge.net/hgroot/crayzedsgui/cegui_mk2 cegui-source

Once you have this, the cloned repository is updated to the default (unstable) code, so you most likely will want to switch to the stable branch instead (be aware that the -C option here will discard any local file changes without additional warning):

hg update -C v0-7

You can also browse the repository from your web browser here: http://crayzedsgui.hg.sourceforge.net/hgweb/crayzedsgui/cegui_mk2/