Thanks to Cracked, I’ve recently learned about Gliese 581c .

From this article.

Of the limited number of planets where humanity might actually be able to live, Gliese 581 c is the closest. But don’t think that means it looks like Earth. Assuming it could sustain life, here’s exactly what you could expect:

The planet orbits a red dwarf, so the sky would always be a bloody crimson. The red light wouldn’t just make you feel strange; it would affect all vegetation, forcing every plant to attain photosynthetic energy from the infrared spectrum. The tangible consequence of that is that every plant would look pitch black.

You would also wake up each day to a perpetual state of twilight. That’s because Gliese 581 c is so close to its star that it doesn’t revolve anymore; one side of the planet always faces the star, and one side stays in darkness forever. The only place where you or anything else could survive is on the narrow strip between the two where the temperature is just right.

And with one side of the planet always hot and one always cold, you can expect some strange weather patterns, with gale winds perpetually surging from the hot to the cold side every day, along with permanent torrential rain, because there are no seasons.

So to summarize: red skies, black plants, gale winds, never-ending twilight and a step too far in one direction could lead to either freezing to death or incineration.

And yet, rather than tiptoeing around that planet and looking for life somewhere a little less terrifying, we’re doing our best to wake up whatever nightmare might be living there already. In October 2008, we sent a message from Earth directly at Gliese 581 c, and it should reach the devil planet around 2029. Then, presumably, misfortune will infest our souls for eternity, but think of how much it will teach us about space!

I had to look up information about the message that was sent: (Bolded bit mine.)

More than half a million Bebo users had got involved in the competition for selecting the messages, and had uploaded their messages onto the social networking site. Several celebrities were also involved in the project, including Sir Patrick Moore, Deborah Meaden, Gillian Anderson and pop band McFly.
…The message also included images of notable landmarks, such as the London Eye and Edinburgh Castle, and of famous people, such as Hillary Clinton, Cheryl Cole and Richard and Judy.
… A senior astronomer from the Search for Extra Terrestrial Intelligence Institute in California, Seth Shostak, had observed that it is unimportant whether the aliens who might receive the messages would understand them.

If anybody’s out there and they find that signal, they at least know that… there must be a planet with some pretty clever things on it.
—Seth Shostak

If I were an intelligent lifeform twenty light years away and I received a message including Richard and Judy, the chief thing I would learn from it was that I needed to head twenty light years in the opposite direction.

[While I was caught in the gravitational pull of Wikipedia I also learned about the types of planets:

• “rock giants” mostly of silicate.
• “cannonball” planets of solid iron.
• “gas dwarfs” mostly of helium and hydrogen.
• carbon-rich “diamond worlds”
• purely hot “ice VII worlds”.
• purely “carbon monoxide worlds”.]