All the names listed above do the trick and a special note goes out to the cognitive scientists: Pinker, Dennett, Minsky, etc.

Carl Sagan was an even rarer breed though. More than just popularizing science: making it understandable and curious, he brought it to a deeper almost spiritual level and let you see both how your day to day life was a part of something so unimaginably huge and fantastic while simultaniously making a good case for our species to push the frontiers.

I don't think anyone can compare. If I had to try I'd pick Michio Kaku, he's a definitely more down to Earth than Sagan, but still great.

P.S. For a bit of history and sociology in the mix I really really suggest you pick up Connections (Season 1) and The Day the Universe Changed by James Burke. It stands beside Cosmos as my favorite TV series and will get your kids interested in economics, sociology and history on top of science.

I'm totally ignorant of the sun/enterprise space of computing hardware. What are these architectures good at that x64/GPGPU aren't going to cover? I've seen in my own career things like SGI Oynx and even high-end rendering cards go to the wayside in favor of standard COTS hardware that is more agile, refreshes more frequently and is blazing fast...

What keeps this SPARC space alive?