formed in a do-it-yourself spirit by relatively new enthusiasts. In many leagues (especially in the U.S.), a punk aesthetic and/or third-wave feminist ethic is prominent. Members of fledgling leagues often practice and strategize together, regardless of team affiliation, between bouts. Most compete on flat tracks, though several leagues skate on banked tracks, with more in the planning stages. Each league typically features local teams in public bouts that are popular with a diverse fan base. Some venues host audiences ranging up to 7,000. Successful local leagues have formed traveling teams comprising the league's best players to compete with comparable teams from other cities and regions. In February 2012, the International Olympic Committee considered roller derby, amongst eight other sports, for inclusion in the 2020 Olympic Games. In 2009, the feature film Whip It featured roller derby and introduced a wider audience to the sport. The WFTDA encouraged leagues to coordinate with promotions during the film's release to increase awareness of the leagues. Furthermore, corporate advertising has used roller derby themes in television commercials for insurance, a breakfast cereal, and an over-the-counter analgesic. Derby names Most players in roller leagues skate under pseudonyms, also called "derby names" or "skater names". These typically use word play with satirical, mock-violent or sexual puns, alliteration, and allusions to pop culture. Referees often use derby names as well, often shown on the backs of their striped uniforms. Some players claim their names represent alter egos that they adopt while skating. Whether a team should skate under real names or derby names is sometimes debated. Some derby names are obscene, a subject of some internal controversy. Copying of derby names has attracted legal and sociological analysis as an example of indigenous development of property rights. New players are encouraged to check derby names against an international roster to ensure they are not already in use. The names of roller derby events are also as sardonic and convoluted—for example, Night of the Rolling Dead (Night of the Living Dead), Knocktoberfest (Oktoberfest), Spanksgiving (Thanksgiving), Seasons Beatings (Seasons Greetings), Grandma Got Run Over By a Rollergirl ("Grandma Got Run Over by a Reindeer"), Cinco de May-hem (Cinco de Mayo), and War of the Wheels (War of the Worlds). Safety Roller derby is a contact sport, and injuries can occur. Superficial injuries include bruising. However, torn ligaments, broken bones, and concussions also occur. Some leagues prominently display their injuries, to