Broadcast Player Action or Achievement?

I'm looking for a way to broadcast messages when players activate a command block. For instance, if I set up a puzzle or a maze or something I want them to click on something at the end to teleport them out but also broadcast a message over the server something like [player] has completed [nameofpuzzle] successfully. I tried the /me command but it doesn't work with command blocks.

Any ideas?

 

Hook the button to two command blocks.

 

Hook up another command block and give it a command like this:

Code:

say @p has completed <puzzle name goes here> successfully!

 

I tried the 'say @p' and it didn't seem to work. It was the first thing I tried since it was the obvious thing to do.
Tried it again this morning and it worked. Go figure.

Thanks!