THIS MOVIE IS LULZ ALL THE WAY, I RECOMMEND.
Watermelon Man (1970)
White insurance man and bigot Jeff Gerber (Godfrey Cambridge)
wakes up one day to find that he has become black.
He spends the next few days trying to become white again.
Comedy ensues as he is slowly forced to accept his newfound blackness.
It's a funny family movie with a message.