Having a brother or sister is beneficial not only in adulthood, but in childhood, as well. You always have someone to play 2 player games with. Every new round is a surprise because a human is not programmed like AI which means more creativity and sometimes insane ideas. Friends can also accompany you in these games. Just decide the game of which genre you want to play. It can be a sports game, racing, fighting, puzzle and so on. You will be able to find any of these. If many friends want to play at the same time, simply make a tournament.