http://www.theregister.co.uk/2008/05/31/discovery_launch/

From the page:

“For those of you not up to speed on space toilets, the ASU failed on 21 May following a “loud noise” – apparently the failure of the air/water separator pump. Despite the ISS crew’s best attempts at DIY, they were obliged to request an emergency plumbing space-lift to tackle the problem.”

Well I never, good excuse for a nice pic though…