In general, I would've thought valentine-shaped features on other planets would be rare, but that's because I'm a cold-hearted, calculating scientist. Turns out I'd be wrong, as this collage of pictures from the Mars Global Surveyor show.

These are all mesas (raised eroded features) or depressions on Mars. My favorite has to be the perfectly-shaped, light-colored tiny heart mesa at the bottom of the crater in picture R09-02121 at the upper right. It's just adorable... even though it's roughly the same size as a football stadium, and the event that formed it was an explosion similar to that of a nuclear bomb!

Higher res version.
Original release.

Image credit: Malin Space Science Systems/NASA