Well, this is something I figured out a little while ago, actually during an extremely dull meeting at work. I couldn't be bothered listening to the idiot - I mean my esteemed colleague - drone on any more, so I sat back and quietly worked out Emma's Theory of Fish-less Cycling.
Urine contains ammonia, and a fair bit of it too. It is also - oddly enough - a sterile product, unless you are suffering from an illness of course. So therefore, it stands to reason that if you put a small cupful of it in the new tank, you'd have a clean, safe (and free!) ammonia source to feed the biobugs and start the cycle off, yes?
Personally, I think I'd prefer to use my own rather than any donated by someone else - however kindly it was offered! - and I suspect that gentlemen fish-keepers might have a much easier time actually collecting the aforementioned urine for use in the tank than us ladies, but hey! Where's there's a will......!