50 Cent posted a video on Instagram challenging Floyd Mayweather Jr. to read a page of a "Harry Potter" novel aloud without messing it up. If Mayweather takes the challenge, and posts proof, 50 Cent said he will donate a cool $750,000 to any charity of Mayweather's choosing. In the video, the rapper says he is forgoing the viral ALS Ice Bucket Challenge in an attempt, it would seem, to try to embarrass Mayweather. A new video posted hours after the initial trash-talking challenge, 50 Cent said Jimmy Kimmel agreed to let Mayweather read on his show. "We don't want to put pressure on you," 50 says to Mayweather in the latest post. "We know you can't pronounce those words in the "Harry Potter" book, so we gonna let you read "Cat in the Hat." The rapper and boxer were once business partners, but since having a falling out, have bashed each other in the media.