This Dec. 20-21 around midnight (PST) there will be a total eclipse of the moon.  This time is only a few hours from the exact time of the solstice.  That is a little unusual, but here is Bob Berman (from new Astronomy Magazine) pointing out another very rare alignment:

"The Moon will occupy a very special place in the heavens that night. Our sky is a carnival of intersecting planes. There is the flat plane of our solar system seen edgewise, defined by the ecliptic. Then there is our galaxy's disk, the Milky Way. These eternal planes meet and cross at the Taurus-Gemini border. Astoundingly, a third plane called the solstitial colure — the sky-circling meridian running through the celestial poles in the precise direction of Earth's tilt — is right there, too.

It's an implausible three-way intersection. And yet that is where — within a few degrees — the Full Moon will stand during the eclipse.

So the Moon will be eclipsed while aligned with the galaxy's plane, Earth's tilt axis, and the centerline of our solar system all at once."