The adjective "Ballmouse" originated in Hull University halls of accomodation. During a LAN gaming session, a particular player would often be disadvantaged in the game by their use of a wireless ball mouse - (as opposed to a corded optical mouse)
During a game of Counter-Strikefor example, a player may screw up their aim, miss, and get a pummeling from another player. One of the other players then yells "BALLMOUSE!" very loudly within earshot of the player that messed up - and raucous laughter ensues.
The word has since evolved such that it may be called out a someone being self-detrimentally stupid or proving their idiocy to themselves through their ill thought out actions.
A party with alcohol. Common variations include: Being in the beanhouse (Being drunk) and bean (an alcoholic drink). Heavily referenced in the LOO$E CHANGE song "Welcome to the Beanhouse"
"It's ya boy GLO, Beanhousin, gettin loose and wild
Silly man, silly water, gettin crazy, wildchild"
"Hey dude, wheres your girl? She's comin to my beanhouse"