(Business 2.0) – Remember the last time you used a paper ticket at an airport? Neither do we. Yet paper still reigns at movies, concerts, and sporting events. Replacing those dead-tree artifacts would eliminate the costs of printing and collecting the roughly $37 billion worth of tickets sold each year. That's why Michigan-based startup MobilRelay is testing a way to store tickets on cell phones. In a pilot project launched in January, moviegoers can buy tickets to screenings at certain theaters using any Web-enabled cell phone equipped with a color display. The ticket then appears on the phone's screen as a bar code. Mobile ticketing is already used in Europe and Asia, but will Americans go for it? That's the big-ticket question.