On the night of Monday, January 21, 2013. Jupiter, the second-brightest planet, appears less than a finger-width from the Moon as seen from North America.
The pair is already very close together at sunset. The time of their closest approach depends on your location; it's around 7 p.m. in the Pacific time zone, 8:30 p.m. Mountain, 10 p.m. Central, and 11:30 p.m. Eastern time. This is an amazing sight to the unaided eye, through binoculars, and in small, wide-field telescopes at magnifications of 40× or lower.
As icing on the cake, the bright orange star Aldebaran shines lower left of Jupiter and the Moon. And binoculars show that the entire event takes place on the outskirts of the Hyades, the closest true star cluster to Earth — with the lovely Pleiades nearby.
In much of South America, the Moon will actually pass right in front of Jupiter, hiding it from view. To find out when the Moon occults (hides) Jupiter for selected locations in South America, see the International Occultation Timing Association website.
This is an opportunity to attempt an unusual feat: spotting Jupiter in the late afternoon, before the Sun sets. First locate the Moon medium-high in the east; then look a few Moon-widths left or lower left of the Moon for Jupiter. It should be easy to spot with binoculars if the air is clear.
Telescope owners have a couple of additional treats. Jupiter's Great Red Spot is visible roughly from 9:00 to 10:40 p.m. EST (6:00 to 7:40 PST). And Jupiter's moon Europa crosses in front of the planet from 8:13 to 10:37 p.m. EST (5:13 to 7:37 p.m. PST). Europa is well camouflaged against Jupiter's bright disk, but it should be easier to spot Europa's tiny black shadow crossing Jupiter from 10:22 p.m. to 12:46 a.m. EST (7:22 to 9:46 p.m. PST).
If you miss this conjunction, there will be another fine Jupiter-Moon conjunction on March 17th.