Today's idiom was "get your head in the game!" It means "you should focus."
For example, in High School Musical, Troy should focus on basketball. During basketball practice, he's thinking about a girl and about singing. His basketball would improve if he would "get his head in the game." Watch the video for "Get Your Head in the Game" here.
Today, we also played Grammarball! Grammarball is a great game that focuses on practicing The Big Three. In Grammarball, you have a scrambled sentence. You must order the words, change the verb, and add any missing articles. For example:
"boy / English / handsome / well / [to speak]" must become "The handsome boy speaks English well."