Run as a Java Web Start application
If you have never used this program before, read below first.
You may be prompted about a "Security Warning" and asked whether you want to accept my security certificate, which is not signed by a trusted authority. For the program to be useful, you need to say "Yes".
This program allows you to make HTTP conections to servers of your choice and see the responses that come back, including header information that you would not normally see if you were using a browser. Sometimes seeing the header information of an HTTP response can be very helpful in debugging something, or perhaps one is just curious about what type of web server a particular site is using (which you can generally tell from the "Server" header).