Here is a good prayer of thanksgiving during your festive meals. It is said it was used by John Wesley and his preachers.

Be present at this table, Lord;
Be here and everywhere adored;
These creatures bless, and grant that we
May feast in Paradise with Thee.

Thanksgiving at meals for the early Christians was more than a formality, but represented their acknowledgement of "foods which God has created to be gratefully shared in by those who believe and know the truth. For everything created by God is good, and nothing is to be rejected if it is received with gratitude; for it is sanctified by means of the word of God and prayer" (1 Timothy 4.3-5, NASB).

Have a great Christmas!