Just in case you missed the announcement on the dot (or chose to forget):
This sunday, January the 25th, we'll be having our second KOffice Bug Day. It will all be about finding as many of the remaining bugs in KOffice Beta 5 as possible. To contribute, just read the bug day's techbase page, check the requirements and visit #kde-bugs somewhen on sunday (starting around 10am CET). As always, no programming skills required.
Is it worth it?
Most definitely. Our last KOffice bug day was a what I'd call a big success with the KOffice developers starting to iron out the bug while we were still triaging and krushing. They are really passionate about delivering good quality release.