Here be my attempts:
Let us worship our Sky Fairy.
Lo, His chin is rather hairy.
He says don't eat meat with dairy,
And that's good enough for me.
Let us worship Cross-Boy Jesus.
In our darkest hour he sees us.
If my prayer does him a-pleases,
I will win the lottery!
If I dissed dear ol' Mohammad,
Would my house risk being bombéd?
Oh, Islam is peace... Osama'd
Kill me with the irony.
Let's worship the One True God.
Hey, don't you think it is odd
The One True God that I laud
Is not the same for thee?
Let us worship Sacred Cracker.
Dear God! That heathen slacker
Is a Sacred Cracker-jacker
And he mailed it to PZ!
(If I may mangle Stephen King for a bit):
See the turtle of enormous girth.
On his shell he holds the earth,
He loves the smallest things of worth,
And even loves a child like me.
(And finally for a bit of further divergence from the meter à la Buggs Bunny):
Ra! Ra! Ra! Ra!
Rah! Rah! Rah!