Here's an interesting little activity. Open a terminal and type netstat. It will show you a list of active connections both unix intercomputer and connections over the internet. (such as connections to websites, instant messenger connections...) At the top of the output, it will show a list of tcp connections. Look under "Foreign Address" for an IP address. (something like 1.23.456.789) There might be something like ":http" after it. Copy just the IP address. Then go to
www.samspade.org . Paste the IP address into the text box there. (there's only one) Then hit enter. You should then see a lot of information about that IP address such as ISP, country, possibly state, and a lot of other stuff. Try entering your own IP address next. Depending on your ISP and where you are located, you might see your country, state, city, zip code, etc. It's amazing what you can find out with just an IP address. If you have a website, you can probably set up something to see visitor IP addresses even.