Let's see... this might be a little hard since I usually break stereotypes, but I do prove:
-That gamers/nerds are socially-awkward, especially in reality.
-That gamers/nerds don't go outside very often.
-That Americans are overweight [small](I'm not really fat, but I'm definitely more pudgy than I'd like)[/small]
-That bronies are gay [small](granted, technically I'm bi, but I do seem to have a preference for the male sex despite being sexually attracted to either sex, so it sorta counts...)[/small]
-That people with asthma don't do very much physical activity.