Unfortunately for this Thanksgiving we'll be with my non-religious (even anti-religious) in-laws. Grace will not be a part of the meal and it will be sort of strange.
I shouldn't be surprised. I once had to give my husband a crash course in how to say the Lord's Prayer, since he was raised in a totally secular home. I am fortunate that he has since embraced belief, even if he is not always consistent in religious practice.
"Bless this food to our use, and us to Thy service, in Christ's Name, Amen."
We can go anywhere, and my kids don't mind bowing their heads for three seconds while I say this unobtrusively. They and their friends all go to parochial school, so they don't think it's "weird" or anything.
-ccm