As it turns out, the actual Richard III probably wasn't such a bad guy. What's more, he probably didn't have any physical deformities. You can learn a lot more about the differences between the historical Richard and Shakespeare's Richard on the BBC's website.
The opening of the play ("Now is the winter of our discontent") is one of the play's most famous lines. This line inspired the title of John Steinbeck's novel The Winter of Our Discontent, and it's an answering machine message in the movie Reality Bites, starring Ethan Hawke.
Groupies have been around for longer than you think. A gossipy anecdote from the diary of a London law student named John Manningham illustrates just how popular Richard III was with the ladies. Here's the famous 1602 entry from Manningham's diary: "Upon a time when Burbage played Richard III there was a citizen grew so far in liking with him, that before she went from the play she appointed him to come that night unto her by the name of Richard III. Shakespeare, overhearing their conclusion, went before, was entertained and at his game ere Burbage came. The message being brought that Richard III was at the door, Shakespeare caused return to be made that William the Conqueror was before Richard III" (source).
In 1996, a private collector discovered a film titled Mr. Frederick Warde in Shakespeare's Masterpiece 'The Life and Death of King Richard III' and donated it to the American Film Institute. It is thought to be the oldest copy of an American feature film to survive completely intact (source).
Buckingham's ghost is rumored to haunt the site of his beheading in Salisbury, which is now a Debenhams department store (source).