UBO meaning in Sports ?

Cal Ripken's Real Baseball, also known as Real Baseball Online or Ultimate Baseball Online, was the first free-to-play baseball based massively multiplayer online sports game (MMOSG). Operating from 2003 until 2008, the game was developed and published by American company Netamin Communication Corporation. The game was designed to allow 18 human-controlled players to compete simultaneously in virtual game, though the number was later reduced due to lag issues. Former Major League Baseball player Darrell Evans served as the game's spokesperson/ambassador prior to Cal Ripken's endorsement of the game. After it ceased operation in 2008, a fan-led open source project was attempted before Real Baseball's successor, Big League Online, was released for beta testing in early 2011.