to play a game is 'jouer (Ã ) un jeu' in French.
'game on' in french is 'jeu sur'
Nous jouons
You say it like this - je joue
As there is no tense in the French language in which you can say "the boys are playing" the closest you can do is say that "the boys play" which translates to "Les Garçons jouent" or "Les Jeunes jouent"
un jeux
le jeu
To play rugby is 'jouer au rugby' in French.
There isn't a name for rounders in French because it's not a French game.
Question is ambiguous. Playing music, playing a game, etc.
Nous avions joué.
'jouer au baseball'
dans ou hors