There's nothing magic here, and you're thinking along the right lines.

The idea is, that if I'm standing on the floor, I'm moving at the same speed as the floor. Naturally I will continue trying to move in a straight line. However, I am traveling in a circle. To travel in a circle, there must be a force applied to me to cause me to curve through space - supplied by the floor.

Anything I "let go" in mid air would immediately assume a straight line of travel, however, I would continue to curve and the object would appear to fall to the floor.

http://regentsprep.org/Regents...6/bcentrif/default.htm
This explains it pretty well. Look at the centripetal force formula to understand why you have to have a really really big radius. Essentially, any distance you move up, say in a house, would have to be negligible compared to the radius. So if your 3 story house is 30 feet up, your radius would have to be:

a = V^2 / r

We want a to be 9.8 m/s^2 so, if our velocity is a sedate 5 m/s the radius would have be about 2.7 m. At 20 m/s, we'd get a radius of 40 meters. (I'm approximating because I don't have a calculator handy. The problem is, 30 feet up, or 10 meters, is 25% less acceleration! Big problem!

So, if we're trying to make a 3 story house be reasonable, then lets say 10 meters has to vary the acceleration 1%. Then 10 meters is 1% of the radius. So 1000 meters of radius, or 1 kilometer, would get you within a reasonable area for it to be negligible. Assuming of course, that you don't have a basement......

Put the formula in excel and play with the numbers.