The back of a buffalo

(video games, informal) A video game, usually based on a sport, where the player must build up and maintain speed or energy by rapidly moving the joystick back and forth.

(idiomatic) To sign one's name on a list when entering a place, to indicate one's arrival. / (computing) To take some action to access a secured program or web page on a computer; to log in.

Ability to be convinced or persuaded.