COLOGNE, Germany - It's not exactly an Olympic sport - not yet, anyway - but as the London Games drew to a close this past Sunday, thousands of professional videogame players geared up for an event that for some can be as lucrative as winning a gold medal. Videogamers have gathered in Cologne, Germany this week for the Intel Extreme Masters (IEM) competition, a professional videogame tournament that runs through Aug. 19. Professional electronic gaming, or eSports, is relatively new and has been gaining popularity around the world in recent years. Germany and South Korea are two hot markets, and the United States is quickly catching up. Pro gamers can earn anywhere from $20,000 to $100,000 or more in winnings and make even more in product endorsements, teaching and other sponsorships. Videogame makers say participating in an event can boost a game's popularity. The IEM event in Germany is expected to attract over 250,000 fans, about 10 percent more than last year, to watch the best videogamers in the world compete in games such as "StarCraft II" and "League of Legends". An additional 20 million people from more than 180 countries will tune in to streams on the Web provided by ESLTV, TwitchTV and CBS Interactive (CBSi) Games. More than 20,000 fans packed the Anaheim Convention Center in California in June to watch gamers compete for over $200,000 in the Major League Gaming Spring Championship. An additional 35 million online viewers streamed matches for games like "Mortal Kombat", "Soul Calibur V" and "The King of Fighters XIII". "The Internet streaming phenomena is probably the biggest reason eSports is having a huge rise right now," said Sean "Day(9)" Plott, a leading "StarCraft II" eSportscaster - pro gaming's play-by-play sportscaster. "Streaming has allowed this huge international representation to view matches live or recorded at any time of day." Multiple leagues now exist with names such as IGN Pro League (IPL), North American Star League (NASL), Dreamhack, Electronic Sports League (ESL), Global StarCraft II League (GSL) and EVO Championship Series (EVO). And some multiplayer tournaments are set up to mimic any professional sports league. Indeed, one game gaining traction among fans is "League of Legends", in which teams of five compete in multiplayer online battle arenas (MOBA). Teams vie for $5 million in prizes in a format that replicates a real sports season and playoffs. "Just like the NBA (National Basketball Association), we expect the competition to intensify in the playoffs - the Regional Finals and the Season Two World Championship," said Brandon Beck, co-founder and CEO of Riot Games, which created "League of Legends".