According to Wikipedia a Palindrome is: a word, phrase, number or other sequence of units that can be read the same way in either direction...
Or, in this case a palindromic video where Dan and naD filmed themselves speaking normally and backwards and doing activities such as eating cake or having a drink forwards and backwards. Totally bizarre and trippy! ;)
More info on palindromes here - Link
Is that some English variation, or did he gack it up off camera?