"Cowboys and Indians" is a great example. For one thing, they're not from India, as incompetently believed; they were the US's indigenous population, largely exterminated through genocide.
(For that matter, the cowboy imagery we pose as was stolen from Mexicans, just like the land we call "Texas".)
Dissidents like Chomsky mentioned, "I clearly remember when I was a child the favorite game for young people was 'Cowboys and Indians.' You went to the forest and pretended that there were 'Indians.' It was like going hunting, like hunting animals." Now, who spends almost as much as the rest of the world combined on military, frequently indulges in international attacks against far weaker people, and jails its own population at the world's highest rate?
Should we also go back to teaching the popular racist version of "Eeny meeny"? "Catch a n... by his toe / If he won't work then let him go." (http://en.wikipedia.org/wiki/Eeny,_meeny,_miny,_moe#Earlier_...)
Who cares about the mountain bike? If I said, "I just got junior a bike and sexual predator kit!" you probably wouldn't even remember the bike, except as bizarre juxtaposition.