Team Fortress 2 features dynamic levels and CVG has the scoop. There is a brief article and a video (that doesn't seem to be working right now) detailing the system.
Update: Apparently there was a new image released as well.
What we did notice is that this is not just a Battlefield type system with some control points 'locked'. When a point is not in play, routes to that section of the map are physically blocked off, so the physical shape of the map is different for every combination of points. That forces you to revise your mental picture of the map, and see it as fresh again.Unless this is something completely different, didn't we already see this in Havana in CS: Source years ago?
Update: Apparently there was a new image released as well.

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