Generally when I engage in textual fisticuffs with a FE'er the first arguement he throws out is "look at the horizon, it's flat!" but fact is that is very, very difficult to tell at ground level.
What proof do I have that this is the case?
Take a look at this youtube thumbnail I snagged from google.


The game is called Kerbal Space Program, and takes place in a round planet universe. Further still the homeworld, Kerbin, is 1/10 the scale of the round Earth. At first glance the curve is hardly noticable, but it is there. Zoom in on the horizon if you need to.

Now I'm not gonna try and use a game to totally falsify FE (although its a useful relatively cheap way to experiment with a RE horizon, especially with the mod that converts the game's system with a full scale RE), because thats tremendously more ballsy then I'd like to bother with. But it does drive a point that the horizon arguement is by far the worst in your arsenal. Simply because if I can hardly notice a curve on a 1/10 scale ball, I most assuredly won't notice it on a full scale one.

For clarity, I'm not saying the game actually disproves FE or proves RE, it just proves the utter pointlessness of one of the more common FE arguements.