Video games are one of today's most popular forms of entertainment. According to the Entertainment Software Association, the U.S. computer and video game industry had software sales of $9.5 billion in 2007--an increase of more than 300 percent since 1996. Two major trends are the growth of mobile gaming and online gaming. Producing and selling successful video games is a huge collaborative effort, often requiring the skills of numerous artists, marketing specialists, musicians, producers, programmers, salespeople, and writers.