If you head over to Google (that's google.com, if you need the URL) you'll find a neat little strategy/card game that someone in Mountain View presumably cooked up in the free 20% of their work day. It's themed around the lunar phases, and sees you face off against a persistently chirpy half-moon in a quest to amass points.

"You'll be over the (half) moon about this new Doodle game series! Join the celestial card game where players must connect the phases of the lunar cycle to earn points and against the October Half Moon. If you're skilled enough to beat the moon, you might just be rewarded.

The game is called Rise of the Half Moon and celebrates the phase of the waning moon. Today is also the last half-moon of October, adding some significance to an already spooky month. According to Google, the half-moon card game is available to play every half-moon and is featured on the website monthly.

This one is called Rise of the Half Moon, and it’s one of those interactive card games. The premise is simple: you play against an artificial opponent and get cards to play with different phases of the moon. You get points if you match cards next to each other, or if you cards “create” a full moon. You also get points for creating a lunar cycle.

Google is educating users about the lunar cycle with its latest interactive Doodle released Thursday. The Doodle commemorates October's last Quarter moon-- better known as a half moon because of its half-full appearance -- before the Waning Gibbous phase culminates in the New Moon.

Google’s famous doodles — the illustrations that show up in place of the Google logo nearly every day — have been known to take the form of surprisingly great games on occasion. Today’s doodle is no exception: Rise of the Half Moon is a strategy card game that celebrates the half moon point in October’s lunar cycle.

How well do you know the lunar cycle? That’s what Google Doodle’s new interactive game series aims to find out. Titled Rise of the Half Moon, it teaches players about the different phases of the lunar cycle,