Most people who aren't Jewish usually don't know what Rosh Hashanah is all about: we tend to think that Hanukkah is the big Jewish holiday, and forget about the others. But Rosh Hashanah -- New Year's Day for people, animals, and legal contracts -- is extremely important in the Jewish faith, as it begins the ten-day period before Yom Kippur, the Day of Atonement. This year, Rosh Hashanah begins at sundown on September 12th.
The traditional symbols associated with Rosh Hashanah are a shofar (a ram's horn, blown to "awaken" people, both in literal and figurative senses) and apples and honey (which represent hopes for a sweet new year). Round challah bread with raisins is also popular.
The great UK blog Crafty Crafty has put together a nice post with a list of links to Rosh Hashanah-themed crafts for kids. There's a little paper shofar made out of a birthday horn, instructions showing how to make apple prints for cards, and links to several different sets of coloring pages, among other things. It's all a fun way for kids to celebrate, or maybe for kids who aren't Jewish to learn a little about the culture of some of their friends.