I don't see this illusion. I've never thought that the moon looked bigger when it was close to the horizon. I think my girlfriend thinks I'm saying it to be difficult but I honestly don't see it. Does anyone else have this experience?
http://en.wikipedia.org/wiki/Moon_illusion#mediaviewer/File:...
I get the same thing with the Ebbinghaus illusion you linked to - there seems to be a very slight difference between the diameter of the two centre circles, but only perhaps 1/4 of the width of the lines. If I stare at it for a while, even that difference goes away. Is that what you see too, or is the effect stronger?