Someone asked me a semi-bizarre question today: the new fonts which are in Office 2007 and Windows Vista, especially Calibri (which, I must say, I think looks great)...

 
Can they be installed on older versions of Windows or Office?

I had never really appreciated all the work that goes into generating a decent font, including getting cross-industry support for stuff like building it into printer ROMs etc. It turns out there's a whole Typography research group within Microsoft - if you're interested in finding out anything more about fonts, I'm sure you'll get it there...

Anyway, the answer to the question is two-fold...