Why not just telnet into the port and type something?
plug@stimpy:/var/log$ telnet microsoft.com 80
Trying 207.46.230.220...
Connected to microsoft.com.
Escape character is '^]'.
asdf
HTTP/1.1 400 Bad Request
Content-Type: text/html
Server: Microsoft-IIS/6.0
plug@stimpy:/var/log$ telnet nerdie.org 80
Trying 208.142.86.4...
Connected to nerdie.org.
Escape character is '^]'.
asdf
Invalid method in request asdf<P>
<HR>
<ADDRESS>Apache/1.3.23 Server at
www.nerdie.org Port 80</ADDRESS>
</BODY></HTML>
Tyler
(text/plain)