E-Sports Entertainment LLC
Professional Gaming League
Turtle Entertainment Online, Inc
The ESEA League is an Electronic sports competitive video gaming community founded by E-Sports Entertainment Association (ESEA). It is widely known for its anti-cheat software. ESEA features a system that allows players of all levels to play matches with others. 
ESEA League began offering lessons to improve gaming skills in 2003 providing instruction in Half-Life, Counter-Strike, and Warcraft III. ESEA created the first professional fantasy e-sports league in 2004. ESEA began its league history with Counter-Strike, but later added Team Fortress 2 (TF2) a game which gained more popularity after its adaption to "Free-to-play" gaming.  ESEA's anti-cheat and player validation software has been adopted by other leagues as well.