[AWsquared]

Lately I've been addicted to The Underground in Sinnoh. Mining is a really fun minigame and I've figured out the system for getting the biggest spheres. I also like the concept of having a secret base Underground. I have a pretty cool secret base underground.
I have never done the Multiplayer because I don't have any people with a copy of Diamond, Pearl or Platinum for Wireless Communication.

Have you ever done anything in The Underground? If so, how often and what do you while under there? Do you just mine or do Multiplayer with friends? Have you made a secret base Underground?