How to jump to running emacs with emacsclient

[Dan Davison]

Using gnome on ubuntu, a shell command like

emacsclient /some/file

switches window focus to the running emacs and visits the file.

I'd like to do this without specifying a file to visit, so that I can
(in gnome) bind a command to a key that will cause my window manager to
simply jump to emacs and show the current buffer. How?

Dan