China is launching to the Moon today! (Weather permitting.) The spacecraft will have a brief, 8-day mission, out to the Moon and back. It is an engineering test for the technology that the future Chang'e 5 sample return mission will need to return its precious samples to Earth. Chang'e 5 is scheduled to launch in 2017.
Some of you may be wondering what happened to Chang'e 4. Chang'e 3 is still operating on the Moon, but there has been no Chang'e 4 yet. Just as with the Chang'e 1 and Chang'e 2 orbiters, there were two lunar landers built in the runup to the Chang'e 3 launch, and the backup spacecraft remains on Earth and may yet be launched in the future as Chang'e 4. The spacecraft that is launching today is not a science mission -- it's an engineering test -- so it's not being numbered as part of the same sequence. It is called 嫦娥五号 试验器, Chang'e 5 Test Vehicle. Unfortunately, there has been some confusion about this in Western media, so you may see media reports about today's launch that name it as Chang'e 4.
Piggybacking on this launch is a mini-satellite called the Manfred Memorial Moon Mission (4M). I know some of you reading this are radio enthusiasts -- I hope you'll post in the comments if you detect the 4M signal! Included in 4M is a radio beacon provided for the Pocket Spacecraft project. (Thanks to Phil Stooke for the links to both of those.)
I have not been following this mission closely since it is not a science mission. Here are some resources where you can learn more: