I've always been fascinated by the cosmos - imagining on a huge scale, in both space and time. I enjoyed the Scientific American imagining visiting the 8 wonder of the solar system; as my daughter said, "it almost feels like it's real!"
I am, however, emphatically disappointed in NASA's Be a Martian site, which allows some web users to help NASA explore Mars. The most obvious problem with the site is that it requires a proprietary piece of software (Microsoft Silverlight) to even use it; in that sense, it's not a real web application at all. Requiring that particular plug-in makes it impossible for anyone using Linux, or any supporter of free software who still uses MS-Windows or Apple MacOS-X, to interact with the site. I'm disappointed that a government agency, funded by my tax dollars, has taken a compelling idea and locked it behind an application which is not free, and which advertises a single commercial software company. I realize this is just part of Microsoft's attempt to replace Adobe's Flash as the dominant platform for rich web applications; it's embarrassing that a government agency has enlisted itself as a participant in that commercial battle. The site does not give much of an opportunity to submit feedback; if you want to contact NASA about it, you might try this email address.