Simulation of WWII on a map that's half-scale of the real Western Europe. Infantry, armor, AT guns, AA guns, fighters, bombers, you name it.
Massively multiplayer, hundreds/thousands on at any given time, 24/7. The learning curve is enormous, but it's a pretty incredible experience. Put it this way, I bought the game in 2001 and I now work for them. :)
If you'd like to check it out, HERE'S the homepage
. It's at the end of a campaign right now, the Axis pretty much cleaned up. There are over 450 entire towns modelled, including some that are enormous (Brussels, Belgium comes to mind.)
If there's no free trial, shoot me a PM, I'll see what I can work out. The game is being re-released as Battleground Europe soon in the United States, has already been released as such in Europe.