do a MUD, you can get free source code if you look
and for those of you who dont know what MUD is, mud is a creation of the elder gamer the ones who long for the console, they are telnet applets codded to be a mmorpg, you simply connect to the servers and go, nothing to DL or configure since telnet is the basis of all internet dos(win too), and linux coms with it, i dont know about Mac, and a java telnet conn. is simple and an easy way of letting people get at it. its about the closest to a video game underground you can get, and with text you have limitless ability to customize the game and put in features
heres a good place to start:
http://www.mudconnect.com/
good luck
oh and i wouldnt suggest VB, its to strict C/C++ is much better s its very flexible. and as for java, i'd say no to that its alittle to weak for my tastes but since your onl doing a text one its fine