GOOGLE HAS OPENED the submissions window for its 2012 student contest.

Grade-school students who are U.S. citizens can now enter with the shot at their artwork becoming the winning Google logo. This year’s theme is: “If I could travel in time, I’d visit...”

“One lucky student artist,” the Internet company writes, “will see their artwork appear on the Google homepage and take home some cool prizes” — including a $30,000 college scholarship and a $50,000 technology grant toward the winner’s full-time school, as well as the artwork appearing on “a limited edition” of the Crayola 64 box.

Prize recipients will include not only that national winner, but also four national finalists, 50 state winners and 250 state finalists competing in five grade groups.

The guest judges include pop hitmaking machine Katy Perry; “Phineas and Ferb” creator Jeff “Swampy” Marsh; “American Idol” champ Jordin Sparks; superstar children’s author Mo Willems; and youth fantasy authors Holly Black and Tony DiTerlizzi.

The deadline? Google says “Doodles are due on March 23, 2012 and must be postmarked no later than March 20, 2012.”

For full rules and more, you can visit the Doodle 4 Google site.