I have read somewhere that the best way to say "to join a club" such as a gym or sports club, would be to say, "Je suis devenu membre du club." Does "rejoindre" mean more or less "to join" as in "to join up with one's friends?" Ex. Je rejoinds mes amis au café ce soir. Tu veux nous rejoindre?" Speaking of the word "gym," is it "la gym" or "le gym?" It seems as if I have seen it used with both genders. Are there other words out there that can both genders and have the same meaning? I realize some words change meaning if the gender changes. Ex. la tour (the tower), le tour (a tour). Merci à tous d'avance. 
