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.