https://en.wikipedia.org/wiki/Hollywood_Stock_Exchange
I used to play this. I'll never forget how much play money I lost on shorting The King's Speech. It had a $15 million budget. Each $1 on the exchange represents $1 million in box office. When I shorted The King's Speech it was trading around $17-18, so people expected it to barely beat its budget.
I had a habit of shorting low budget movies that I thought were too boring or low concept. It was actually my most effective strategy and made me the most money(again, not real money).
I thought I had a steal since I thought it would bomb and they wouldn't even break even. Then it is an immediate hit, makes like $140 million in the USA and goes on to make $400 million internationally.
The King's Speech annihilated me