Whilst it's theoretically possible to observe the Coriolis effect in water draining out of a bowl, it would be incredibly difficult, due to the speed with which the water drains out and the lack of precision with which a toilet bowl is made. Many other factors are likely to influence the direction the water flows, if it even flows in a spiral at all.
There are, however, a number of other phenomena that are explained by the Coriolis effect. Weather systems, ocean currents, pendulums, stuff like that. It's unfortunate that people frequently make the mistake of using examples such as this, as people round here tear it apart like ravenous tigers.
By the way, the FE explanation for the Coriolis effect is some bizarre hypothesis called 'Gravitational gearing' or something like that.