What is this simulator like device called? The following link: http://www.youtube.com/watch?v=I13wJyUZL_4 has a man limp to a bike (a Pinarello) leaning against a wall, climb on to it and ride the bike for a good minute to a minute and a half, while remaining stationary. My question is:


What is the simulator like device called? It looks like a bike treadmill, but what is it called?
How does the bike remain stationary on that device for all speeds? I would imagine that the bike would be stationary for only higher speeds, but that does not seem to be the case.
What are these devices used for? 


Any insight on the above is most welcome.
Rollers. You have three drums, two at the back, one at the front and the front roller is powered by one of the back rollers. You can also get add ons to give you a breeze:



Balance is what is needed to stay on the rollers, also a wall (as per featured video) comes in handy.

Rollers are used for training purposes although they can also be used for demonstrations at trade shows etc. When riding rollers instead of an exercise bike you do need to balance as well as push the pedals, you can therefore improve your riding, not just your strength/endurance.