fun and games vs mirth

fun and games

noun
  • Recreation; nothing serious; easy, enjoyable activities. 

mirth

noun
  • The emotion usually following humour and accompanied by laughter; merriment; jollity; gaiety. 

  • That which causes merriment. 

How often have the words fun and games and mirth occurred in a corpus of books? (source: Google Ngram Viewer )