I always got the Stargate SG-1 DVDs as soon as they came out, but I finally started catching up on going through all the bonus material.

On the 5th Season DVD, in the directors commentary, Peter Deluise made up the following lyrics.

Stargate,
It’s a great big world...
With a great big swirl
    that you step inside
        to another world.

We’re talkin Stargate,
It’s a crazy trip,
You can go quite far
    and you don’t need a car
        or even a ship.

There’s Colonel O’Neill and Carter and Daniel and Teal’c.

Look out for that Goa’uld.

Someone captured it over on Google Video:  SG-1 Theme song lyrics sung

Dorky but Awesome!