For those who have yet to catch some of the virtual sites in SL here are a few highlights. All of locations can be easily found by the search function within SL.
Trinity College of Dublin, has a splendid SL site, complete with recreations of their historic buildings and a virtual campus. Since it was Sunday when I visited, I assume they were all in the Chapel building.
The question of language inside SL is an interesting one, and I am happy to report that it is possible to communicate in Japanese within SL. At the moment there is no translation, but if you can type in Japanese on your computer, you can mingle with people from all over the world. SL is currently expanding into Japan, Korea, and Europe. A
Japanese Forum (above) is available in SL and online.
NASA videos can be seen at the above location, along with a star map (dome building).
USC Annenberg School of Communication has an interactive forum at the above location.