Lol @ Crumpet et al.
Seriously, I'd simply go with "my god" (which you can think upper- or lower- case as you please).
It's how the Greek translators chose to "render" the obscure 'El-Shadday in Genesis 17:1 etc. Not "I am God Almighty," but "I am your g-God".
Other than that, I like the idea of the "unknown god" in Acts 17:23.