Exploring your mind could also mean exploring the world around you as it's all in your head anyway... do something you've never tried before especailly if it's something you've WANTED TO DO for a long time. Or try talking to your friends and/or family and try to understand where they are coming from... put yourself in THEIR shoes... that's mind expansion. You can also try meditation but you've got to be able go all the way and dedicate yourself for that.