TrackMania 2 Canyon, TrackMania 2 Stadium, and ShootMania Storm, all developed by Nadeo, are now available for purchase or pre-purcahse on Steam. They were previously available exclusively from Nadeo's site, but it seems as if the developer has had a change of heart. Stadium and Storm both have demos available, though I wouldn't be surprised if the "demo" is simply the open beta access.
I'm glad Nadeo is bringing these games to Steam, since it will definitely bring in a larger audience. I have been having an absolute blast playing the ShootMania Storm beta and am anxiously awaiting the full release this April. I may as well take this opportunity to also check out Trackmania 2 Stadium, also releasing in April.