The Tech Museum of Innovation in San Jose, CA has created The Tech Virtual. A place where you can design your own virtual exhibits, and explore. In her profile, Avi Marquez, describes this crossover project, happening in SL and at the RL museum, to contain

What a unique use of photos and prims
to create The Museum of Natural History of Vienna. The exhibits will
change there, but right now there's a unique Steampunk insect exhibit. Rikomatic has posted a really neat video tour of the location as well.

Students from the University of West Scotland's Collaborative Virtual Environments Class have created a build at VirtuALBA that showcase three immersive exhibits.

Dinosaur Park is "Jurassiac Park meets Second Life"! This place was completely fasicinating to me and my friends the first time we went. I went by later on by myself to explore a little on my own, and found that it's really a lot more than just a

To the Stars and Beyond! Astronomy and Planetarium by Magnuz of Sweden. Magnus Zeisig, one of Sweden's leading SL builders, has created a planetarium exhibit on Honawan that is a must see! It contains a number of stellar exhibitions, including large, interactive space spheres, advanced interactive celestial body models, and space dioramas.

A while back The Abyss was featured as Landmark of the Day...they have had a complete overhaul of their experience since then, and I think it would be a great treat for you to visit! I am attaching the note card that describes the attraction! Enjoy!

Real time weather map built on a huge sculptie Earth. Brought to you by Zee and Zora! There's a bit more to see there... http://slurl.com/secondlife/Areumdeuli/88/92/105Pasted from the notecard:The project is called Sculptie Earth and it is a large scale topographical model of the earth constructed from sculptie prims, and it features a cloud layer that displays a realtime satellite feed of weather conditions that shows 48 hours of cloud data that is updated ever three hours.

Images available here

Well Scientists and mathematicians, you're going to love this!! This is the museum associated with The Exploratorium - the museum of science, art and human perception in San Francisco...they've created this place to allow you to interact with science and experiment with as much as you want! Lots of interactive displays....I spent a lot of
time just clicking things to see if it would do something!! Have fun! http://slurl.com/secondlife/SploLand/183/78/26

Images available here

(archived from the Best of Second Life) For the Trekie fan, the Star Trek Museum of Science will give you
hours of enjoyment. Within this attachment you will find many landmarks
having to do with this 4 sim project. The original Enterprise is in the
process of being built, so make sure you go back to visit this
one! Thank you to Araucano Janus for sending us to this great sim! Don't
forget to tell your friends about The Best of Second Life! http://slurl.com/secondlife/TovaDok%20II/71/209/22

Images available here

The Avnet Technology Museum. The displays you will see span 84 years
of innovation. They include historic documents and photographs related
to the technology industry, and memorabilia from Avnet and other key
firms that have played important roles in the evolution of the
electronics industry.See technology artifacts from WWII as well as the
advent of the personal computer!Thanks to Zee Pixel, curator of this
great museum, for sending it my way! http://slurl.com/secondlife/Avnet/150/154/39

Images available here