A5 = A, E
Bb5 = Bb, F
G, A, Bb, D, E, F
Now, you have the basis of the scale from the chords.
It's going to be some kind of G minor scale/mode from the Bb (flat 3). You can throw any kind of C you want in there and make up your own scale, since it's not implied by the chords, or you can pick a mode.
You have the 1, 2, b3, --, 5, 6, b7. The obvious mode is Dorian, since you have a b3, b7, and 6, so that makes the missing note a 4, which is C.
Depending on how you play the chords, however, you may want to choose another mode. If you're going the heavy metal route you may want to play G Phyrgian, Aeolian, or Minor Pentatonic. Aeolian or Minor Pent. for the rockers, Dorian for the jazzers, or Phyrgian for the Spanish sound. It's all in what sound or mood you're trying to capture.
"You must stab him in the heart with the Bone Saber of Zumacalis... well, you could stab him in the head or the lungs, too... and the saber, it probably doesn't have to be bone, just anything sharp lying around the house... you could poke him with a pillow and kill him."
- Aqua Teen Hunger Force, The Universal Re-Monster
- Aqua Teen Hunger Force, The Universal Re-Monster
