What? No Klingon?
QISmaS DatIvjaj 'ej DIS chu' DatIvjaj (sg)
QISmaS botIvjaj 'ej DIS chu' botIvjaj (pl)
Happy Holidays to you too.
Merry Christmas in Elvish - Ná merye i turuhalmeri!
Merry Christmas in Binary Code - 01001101011001010111001001110010011110010010000001 00001101101000011100100110100101110011011101000110 11010110000101110011