The Internet has opened up a whole new world to public participation in science projects both big and small. These were usually restricted to the in-crowd but are now available to anyone with a computer. The level of participation can be very active, as in the case of GalaxyZoo.org (more on this later), or very passive like in Folding@home and SETI@home.
Sometimes, they are a one time deal that can still be very exciting to participate in. Akatsuki (Japanese for dawn) is one such opportunity. Akatsui is a Japan Aerospace Exploration Agency (JAXA) space mission to study the planet Venus. The Akatsui Message Campaign is a public outreach effort for the mission, which allows people to submit a very short message that will be printed onto an aluminum plate what will be attached to the Akatsui spacecraft.
The deadline for submissions is January 10, 2010. Sorry for the late notice but I just found out about it. I should add, although the slogan for this outreach program reads, “We will deliver your message to the bright star Venus,” Venus is actually a planet. But, you already knew that. Thanks to my friend Robert Sparks for the info.