All of about a year ago my family upgraded to high speed cable internet, and immediately we went out and bought ourselves a spiffy wireless-enabled router; the reasoning was that since Stephan was going to be on the other end of the house from the wireless router, we should go ahead and use wireless for his connection and drop cables through the walls for the other computers. And thus you see why wireless was enabled for our household in the first place.
At the time, I thought "I should properly secure this." But instead, I just took some minor precautions and headed back to college. Having been back for a few months, I've noticed odd periods where the connection appears to die. These I attributed to noise on the wire that was causing a problem with our cable connection, and shrugged it off.
Tonight, Stephan turned on his computer and discovered that he couldn't get connected to the internet. I logged in to the router control panel and discovered that each of the 3 IP addresses (for each of the three computers in the house) was in use. Except...Stephan's wasn't the third!
Well shoot, someone's accessing our network. It wasn't hacking because the door was wide open, but it still feels like we were invaded. I checked the router logs and discovered that odd websites were being accessed from our home network, like sfhty.com and seksyat.net, both of which are Arabic sites.
Obviously, a terrorist was using our internet connection! I immediately locked things down tight. There are still some security measures I could take, but we're now safe from casual terrorist infiltration.