- You could dress up as an ancient roman?? Toga...sandles etc.
Thats when the Bible was set I think.
- You could go as Gabriel, the angel.
- You could go with someone as Adam and Eve.
- you could go as satan
- You could go as one the ancient greek gods...
zeus (ruler of the gods, lord of the sky, the rain god, has thunderbolts which he hurls at those who displease him)
poseidon (god of the sea - he has a trident 'which can shake the earth, and shatter any object')
hermes (he leads the dead to go to the underworld and is the fastest of the gods, think winged sandals, a winged hat, a magic wand)
there's also apollo (god of music, light, and truth), ares (god of war), hades (lord of the underworld)
Hope this gives you some ideas. I was stuck by the theme at first - but you can make it quite good!