A game invented for when you are incredibly bored and have no resources available to you to play a game (such as a ball). It involves two players which similtaniously have to invade each others personal space, such as waving their hands infront of the opponent's face or almost licking their necks.
The game is won by causing your opponent to flinch or deliberately move out of the way of your attacks. However, you can loose by touching them accidentaly.
John: Lets play Personal Space Invaders.
Mike: Yeah, alright.