EnableProposed
To enable the proposed archive for hardy add the following line to /etc/apt/sources.list:
{{{deb http://gb.archive.ubuntu.com/ubuntu/ hardy-proposed restricted main multiverse universe }}}
Or go to System -> Administration -> Software sources and tick the hardy-proposed box under the updates tab.
Enable Apport
When running proposed it is also useful to enable Apport bug filing to capture and report crashes. You can enable Apport on a stable system with:
{{{gconftool -s /apps/update-notifier/show_apport_crashes --type bool true }}}
To test that Apport is now running, enter the following command to cause a simple crash and generate a crash file in /var/crash: {{{sh -c 'kill -SEGV $$' }}}
This should notify about the crash and offer you to submit it to Launchpad. Click on 'Report' and verify that the details look complete (package name and version, has a (broken) stack trace, etc.). Please do not actually send it to Launchpad, though, since it is not a genuine bug.