Alarm Clock – A simple clock where it plays a sound after X number of minutes/seconds or at a particular time.
RSS Feed Creator – A program which can read in text from other sources and put it in RSS or Atom news format for syndication.
Chat Application (IRC or MSN Style) – Create a chat application that can carry on simple chat rooms like on Internet Relay Chat or a more direct chatting style like MSN. For added complexity, create your own protocol to facilitate this chatting.
P2P File Sharing App – Create a program like LimeWire, FrostWire, Bearshare, or a torrent style application.
Port Scanner – Enter an IP address and a port range where the program will then attempt to find open ports on the given computer by connecting to each of them. On any successful connections mark the port as open.
Mail Checker (POP3 / IMAP) – The user enters various account information include web server and IP, protocol type (POP3 or IMAP) and the application will check for email on several accounts at a given interval.
Packet Sniffer – A utility program that will read packets coming in and out of the machine along with related information like destination and payload size.
Remote Login – Create a remote desktop style application which can see and control the remote computer (given you have permissions). It may require the use of your own private network and a second computer to test with.
Site Checker with Time Scheduling – An application that attempts to connect to a website or server every so many minutes or a given time and check if it is up. If it is down, it will notify you by email or by posting a notice on screen.
Web Bot – An automated program which carries out tasks on the web including checking websites, page scraping, and summarization of data or web posting.
Chat Application (remoting style) – Create a chat application which allows you to connect directly to another computer by their IP through the use of remoting and allow your “server” application handle multiple incoming connections.
CAPTCHA Maker – Ever see those images with letters a numbers when you signup for a service and then asks you to enter what you see? It keeps web bots from automatically signing up and spamming. Try creating one yourself for online forms. If you use PHP, take a look at the image functions of GD.
Traffic Light Application – See if you can make your own street light application and then put it into an intersection scenario. Don’t let any cars run the lights and crash into one another!
MP3 to Wav Converter – MP3 is essentially compressed wav format. See if you can translate it back into wav so that some other sound editing programs can work with the wav file itself. Keep in mind that 1 MB of MP3 is relative 10MB wav.
Find Way Out of Maze – Develop an algorithm that allows a mouse to navigate through any maze given enough time.
Guitar Hero Clone – Create your own version of guitar hero where you can incorporate your own music and allow the user to press keys for the various colored notes. Judge their accuracy.