to run it in VirtualBox, the livecd needs "xmodule=vesa" boot option. To install VBox/nVidia graphics drivers, you need to install dbrs-precompiled-linux-sources-2.6.28 (using apt-get).
And OO 3.1 is at "deb http://ppa.launchpad.net/openoffice-pkgs/ppa/ubuntu hardy main" repository.
Very lightweight on my 5 yr old laptop - with the OpenBox option.