Its possible to set up your own grid and if you want, use it behind your firewall. The Opensim software runs on both Windows and Linux. With a VPN connection you can meet and conference on your own operated islands behind the firewall.
You can find more on the Opensim software on this pages. Opensim.org
We do terraforming and construction of Islands and supply them in the oar file format. We also supply buildings and land files.
Some of them for free you can find more in the download section of the website.
The OSGrid is a great way to show of different oar files or test half ready stuff. The island will change from time to time and sonmetimes it will blow up in our face and not be online att all. But it have been up for three months without any interrupts once, I am proud of that.
I am trying to put out stuff here and do some freebe stuff to.
You need a account on the OSGrid (its free) to go to the island. OSGrid homepage.
The Osgrid island is often moving around (you do not have your place on the grid) but a map search for Nilsart or 2worlds2go will do it.
You do not need a supercomputer to run a island. Its often enough to use some older computers beacause the server software do not need to run any graphics. We use a MySql database on a OPENSuse installation.
We have tried out a windows XP installation and it works well.
Right now we use the XP machine to run another flavor of Opensim the Realextend software Real extend homepage
Opensim is not the Second life server but its a very good way to test crazy ideas without crashing the Linden lab servers. Connections from the web to the grid. Moving and self reproducing scripts. A skyscraper script that suddenly goes crazy and make a 2000 flor building. You get the picture.
And thru a VPN tunnel its possible to sit anywhere in the world and still cooperate and test silly stuff for all developers on the internal web. Its kind of cool.