This adaptation by David Haas is a blast and just in time for Christmas.
The sheet music of his version is available to purchase at GIA, where the text is hidden in their preview.
“Gaudete” is a renaissance song collected in Piae Cantiones. Other versions (eg here) are around for free as it is public domain. I gather the original had no tune for the verses, but most use the same tune as Haas.
My version is not serious: