Well, if you need extra practice, you can try and write one of the programs I had to write for school. I took a Java programming class my senior year of high school. Albeit the two languages are different, the program could probably be modified to work on both. Another thing you could try is what me and some of my friends tried and that is to write a server program that listens for connections. Then use Telnet to connect to the server program. I made a real simple chatroom program, but with the right program layout you can use it to send information between the server and telnet, or even write a client side program, such as, say, a Bank Server and a Client program to access the bank and saved bank accounts. It'll really give you some ideas on what else to try as you're doing it and you can have some fun making it increasingly more advanced.