HELP! I CAN'T STOP PLAYING LEAGUE!

Literally! The client works fine but the close icon won't work! HELP! I WANT TO DO OTHER STUFF BUT THE GAME WON'T LET ME! D: I CAN'T KEEP PLAYING! I HAVE FOOD TO EAT AND A BLATHER TO EMPTY AND THIS MYSTERIOUS WORLD OF "OUTSIDE" TO GO TO! D: