Yes, this is a Dexter's Laboratory zodiac calendar.
It's a random idea I know, but ~Misora-Roll
reminded me the other day of this idea which I probably had like 2 years ago now. Dexter and Dee Dee are canonically a Capricorn and a Cancer, and I just thought it would be fun to assign star signs to the other characters. In a few cases it actually worked out really neatly (Mandark being a Scorpio, for instance, which is compatible with Cancer and which is a Mars sign like his sister, which I made an Aries).
Oh, and be sure to full-view so you can see all the details. What's your sign, baby?