I help run the Science on a Sphere systems at the Science Museum of Minnesota. As a matter of fact we just hosted the user's conference, bringing people together from all over the US, Mexico, and various parts of Asia who run these systems. It's a fun network of scientist, educators, and museum exhibits people.

Because the network is aimed at a technically and scientifically diverse community community the data catalog is actually well organized and mostly easy to understand. I'm continually telling data viz friends to check out the resources in there for their non sphere projects:

http://sos.noaa.gov/Datasets/index.html

Fun fact: NOAA just installed the 100th SOS system.