They're building a time capsule, and your message to the future could be in it. Very cool project.
The time capsule will be sealed in Copenhagen, during the climate summit. Part of the idea is to get delegates thinking about which future they're creating. Part of the idea is just to, well, say something nice to the future world.
Here are a few of my favorites.
You can send a message and also vote for which ones go in the time capsule.