The Digital Urban blog has a pretty continuous stream of nifty explorations into all manner things in the intersection of CG and Architecture - indeed technology and cities. They have been working with game engines for quite a while now, doing some pretty nifty things with Oblivion for example - check their site for plenty of examples.
Well now that we have Crysis and its mighty CryEngine2, the Digital Urban guys are trying it out as well. They have been importing their sample city and a range of other models of their own and even from the GoogleWarehouse. Diving into exactly this area is high on my todo list after my two current COFA courses are done.
These are the most relevant posts:
Crysis - Importing Architectural Models
Cities in Crysis Sandbox Editor
Check out these vids of their progress with the engine: