Head to the concession stand at select theaters and get your LidRock featuring the HowStuffWorks Trivia Challenge -- yours free with any 44-ounce soft drink! Play the HowStuffWorks Trivia Challenge and compete for over a thousand cool prizes. Win movie tickets, the latest electronics and more! Ask for your LidRock at the concession stand today! Learn more from HowStuffworks.com -- because it feels good to know.