Voyager Golden Record
From Wikipedia

The Voyager Golden Record is a gramophone record, attached to the two Voyager spacecraft launched in 1977, containing sounds and images selected to portray the diversity of life and culture on Earth. It is intended for any intelligent extraterrestrial life form that may find it. The Voyagers will take about 40,000 years to come close ("close" meaning in this case about 1.7 light years) to another star, hence if other beings do not come our way to meet them, it will take at least that long for the Golden Record to be found.
As the probes they are attached to are relatively small and will be all but lost in the vastness of interstellar space, it is extraordinarily unlikely that they will ever be intercepted. If they are ever found by an alien species, it will be far in the future, and thus the record is best seen as a symbolic statement rather than a serious attempt to communicate with aliens.

The Voyager spacecraft will be the third and fourth human artifacts to escape entirely from the solar system. Pioneers 10 and 11, which were launched in 1972 and 1973 and preceded Voyager in outstripping the gravitational attraction of the Sun, both carried small metal plaques identifying their time and place of origin for the benefit of any other spacefarers that might find them in the distant future.
With this example before them, NASA placed a more comprehensive (and eclectic) message aboard Voyager 1 and 2 – a kind of time capsule, intended to communicate a story of our world to extraterrestrials.
This is a present from a small, distant world, a token of our sounds, our science, our images, our music, our thoughts and our feelings. We are attempting to survive our time so we may live into yours. — U.S. President Jimmy Carter.

Contents

The contents of the record were selected for NASA by a committee chaired by Carl Sagan of Cornell University. Dr. Sagan and his associates assembled 115 images and a variety of natural sounds, such as those made by surf, wind, and thunder, and animal sounds, including the songs of birds and whales. To this they added musical selections from different cultures and eras, and spoken greetings from Earth-people in fifty-five languages, and printed messages from President Jimmy Carter and U.N. Secretary-General Kurt Waldheim.
After NASA had received much criticism over the "smut" on the Pioneer plaque (line drawings of a naked man and woman), the agency chose not to allow Sagan and his colleagues to include a photograph of a nude man and a nude, pregnant woman on the record. Instead, only a silhouette of the couple was included (Jon Lomberg: "Pictures of Earth". in Carl Sagan: Murmurs of Earth, 1978, New York, ISBN 0679744444).
Here is an excerpt of President Carter's official statement placed on the Voyager spacecraft for its trip outside our solar system, June 16, 1977: "We cast this message into the cosmos ... Of the 200 billion stars in the Milky Way galaxy, some – perhaps many – may have inhabited planets and space faring civilizations. If one such civilization intercepts Voyager and can understand these recorded contents, here is our message: We are trying to survive our time so we may live into yours. We hope some day, having solved the problems we face, to join a community of Galactic Civilizations. This record represents our hope and our determination and our goodwill in a vast and awesome universe."
The 115 images are encoded in analog form. The remainder of the record is audio, designed to be played at 16 revolutions per minute. It contains spoken greetings beginning with Akkadian, which was spoken in Sumer about six thousand years ago, and ending with Wu, a modern Chinese dialect.

Journey

Voyager 1 was launched in 1977, passed the orbit of Pluto in 1990, and left the solar system (in the sense of passing the termination shock) in November 2004. It is now in empty space. In about 40,000 years, it and Voyager 2 will each come to within about 1.7 light years of two separate stars: Voyager 1 will have approached star AC+79 3888, located in the constellation Ursa Minor; and Voyager 2 will have approached star Ross 248, located in the constellation of Andromeda.
The Voyagers are identical but on different flight paths. In May 2005, Voyager 1 was 8.7 billion miles from the Sun and traveling at a speed of 3.6 AU per year while Voyager 2 is about 6.5 billion miles away and moving at about 3.3 AU per year. One 'AU' equals the distance between the Sun and Earth, or 93 million miles.
Voyager 1 has entered the heliosheath, the region beyond the termination shock. The termination shock is where the solar wind, a thin stream of electrically charged gas blowing continuously outward from the Sun, is slowed by pressure from gas between the stars. At the termination shock, the solar wind slows abruptly from its average speed of 300 to 700 km per second (700,000 - 1,500,000 miles per hour) and becomes denser and hotter. [1]
As Carl Sagan has noted, "The spacecraft will be encountered and the record played only if there are advanced spacefaring civilizations in interstellar space. But the launching of this 'bottle' into the cosmic 'ocean' says something very hopeful about life on this planet."
Some others suggest that the only civilization that will encounter it will be our own, when in a few hundred years it is retrieved and placed into a space museum.