Crackerjack
This term dates back to the late 1800's, and means "superb" or "excellent"

In 1896 the name was trademarked for the caramel popcorn product. In 1908 Jack Norworth wrote the lyrics for Take Me Out to the Ballgame, which mentioned the name of the candy propelling it to fame. This song is now sung during seventh inning stretches at baseball games.

(来源：最老牌的英语学习网站 http://www.EnglishCN.com)