If you 'convert' the phrase 'Cute Purple Dinosaur' to latin (ie. replace U with V), extract the letters of the Roman numerals and add them up... the result is 666.
Cute Purple Dinosaur
Cvte Pvrple Dinosavr 'Latin-ised'
C V V L D I V Extract Roman numerals
100 + 5 + 5+ 50 + 500 + 1 + 5 'Convert Roman to alphanumeric'
= 666
Thus, this proves that Barney, the cute purple dinosaur, is Satan!
PS. if there are any really young ones here who like Barney, I'll just say now that it is a joke and not true in any way...