This is so useful (to a developer) that I'm blogging it so I have a record of it when I need it in the future. You know how you can test a webserver by opening a telnet connection to port 80? Well by the magic of OpenSSL you can do the same thing on port 443.
openssl s_client -connect example.com:443 -state
Then you just type away the same as if it was a normal telnet session to port 80, i.e.
GET /some/url HTTP/1.0
server response here...