all you need is a unified force pushing you away from the earth at 9.8m/s^2. air jets could work on a very basic level, but you'll still have the aerodynamics to worry about, so it wouldn't be a perfect "weightless room" (I assume that's what we're going for here). you could theoretically acheive it with a magnetic suit and an electromagnetic floor, but there's nothing to stop that from flipping you over and gluing your head to the ground. What it would take is a force that consistantly pushes all matter away from it placed between you and the body of gravity. An equal force would make you weightless. Such a force exists on the molecular level (the name of it escapes me) but i'm not sure we've quite harnessed that one yet.