I´m fairly sure that when a comercial airliner with 4 engines is about to take off they take the engines to full throtle, but the plane doesn´t move while the brakes are one...

as to why this happens?....I´d guess that the combination of friction between the tires and the ground and the inertial of the airplane are "stronger" than the jet engines.
I saw the tv show and I think they had 2 trucks, one with one engine each, I guess the same principle as the plane takes place, I remember that the trucks didn´t look to be tied down or anything.

Mythbusters is great....my favorites are allways anything that envolves explosions....which in that show tends to be a lot of the experiments


Top Gear is a great show also.....my favourite moment is the Lotus Exige test, they went and got an Apache Helicopter and put the car´s manoverability against the chopper.....very cool the guy from the show looked like he was really having a blast driving the thing.