Hey you guys,
I'm not sure if you've heard about
MineCraft, but I'm guessing it appeals a fair bit to the Roguelike crowd! It uses Java and is an applet, so the best way for you guys to find out if you like it is to go and try it!
Basically, you're in a block (think 3d matrix) world, where you can remove and add blocks more or less at will. That's it. It has multiplayer, and around a dozen types of blocks, some of which interact with one another. The great thing is the open-endedness of it. You can just go and do whatever you like, castles, ruins, ... well, WHATEVER you like.
You can play for free right now, but as the game evolves and new features are added, they might no longer be available unless you buy it. It's currently at $15 or 10€. For example, if you buy the game you can make custom skins (I have a pirate, harrrrr).
I'd highly recommend you guys give it a twirl, you might just enjoy it!