I D Unknown

Brought it in last night when I noticed the huge bud. Had a nice light scent.
Not as large as the type I used to grow which had the amber or dark gold back petals
That one might have been an oxy

That looks like Epiphyllum Hookeri: http://davesgarden.com/guides/pf/go/2100/

I have a very large one that just bloomed last week but I couldn't detect any fragrance on mine.

Lovely photo!

I've just compared your photo to mine and I think yours is the same. E. Hookeri in the link I posted above.

Here's a photo I took of one of my blooms on Sept 13th about 11:30 at night.

Thanks Lin. They do look very similar