Today is Star Trek Day, in commemorate of the first broadcast of TOS on September 8, 1968. So break out the boxed set of DVDs, your evening is booked.
There is no official recipe for Romulan Ale. Or rather, there are several official recipes, which is basically the same thing. So just do whatever feels right, as long as it's bright neon blue, and let everyone know how it goes. The most common source of color blue curaçao; apparently at least one episode used Glacier Ice Gatorade for the appropriate effect.
Of course as everyone knows, true warriors drink prune juice.