http://img696.imageshack.us/img696/2825/screenshot20120120at842.png
^The entrance to the Virtual arena
The virtual Arena is a never-ending simulator that has no drops. There are 10 separate arenas, 6 for monster families and 4 for statuses.
When you enter the room, you are assigned to a party within the same tier you are currently in. You can invite and go solo here.
The arenas are the same as any normal arena, exempt there is a no-monster gate at the south (entrance) and north (empty area to change gear). When you clear a wave, another one will spawn. This will go on forever, even if you leave the arena level. Only 4 knights are allowed in a arena at a time.
Pros:
Area to test gear
Something to do when ME is out
Cons:
...
Well, besides the fact that a lot of people don't go into the Advanced Training Hall after their first time, this could be interesting. I think it's a little complex for the Training Hall, since everything else is very basic. Especially the tier-separation. Sounds like something you'd find in a Krogmo Mini-game.
Technically, the shufflebots are there to test gear, since they are normal to every damage type, although they are only T1.
When ME is out, Krogmo games are the way to go. You need loads of them for things like Voltedge, and Blast Network is fun anyway. Lockdown is still broken, but some people like that too.
~Sev