4. Mad Love: The Origin of Harley Quinn
No one can deny that we have now finally seen a definitive Joker on screen in Heath Ledgers iconic performance. But what about his sidekick and sometimes-girlfriend Harley Quinn? Will we ever get a chance to see her on film? Harley was an original creation for Batman: The Animated Series, but became such a popular character that she was brought into the comics canon as well. Her origin story, Mad Love, has a plot that would translate perfectly on screen. Harleen Quinzel, a psychology grad student assigned to work at Arkham Asylum, takes a special interest in the Joker and eventually falls in love with him. When he is trussed up by Batman during his latest escape, Harleen decides to break him out herself, taking on the moniker Harley Quinn. Her first appearance in the Harley costume, during the break out, is not a moment soon forgotten.