There are a number of Latin renditions of "Rudolph the Red-Nosed Reindeer" — this site collects a bunch, both in the main text and in the comments. The first version is listed as "translator unknown, widely repeated on the Internet," and indeed, this is the version I first came across. Dissatisfied with the Latin grammar and rhymes, I instead wrote the following — loosely based on the original but substantially altered — which you are free to use in caroling this holiday season:
Rudolpho cervo erat
Nasum ruber lucensque;
Quicumque hunc videret
Hunc diceret candere.Alii cervi omnes
Semper hunc deriserant;
Cum misero Rudolpho
In ludis non luserant.Sanctus Nicholas dixit
Sub festum nubilum:
"Naso claro, Rudolphe,
Hodie carrum ducesne?"Tum cervi clamaverunt,
"Omnibus dilectus es!
Rudolphe rubri nasi,
In historiam descendes!"
For an entirely original one — though this one is a lot harder to sing — try my rewriting of the same carol in the style of Catullus (hendecasyllables). I'm going from memory here, so I hope this is right:
De Rudolpho cervo rubri nasi
Lucens et rubicundum erat Rudolpho
Cervo nasum, aliquo umquam idem vidente
Quod et fulgere saepe diceretur.
Irridere alii hunc iocis solebant
Cervi, cum quibus haud ei licebat
Ludos ludere idoneosque cervis.
Sub festum nubilosum honore Christi
Tum Sanctus Nicholas ei appropinquat --
"Carrum duc hodie, Rudolphe," dicit,
"Tuo tam nitido calente naso?"
Cervi omnes igiturque diligebant,
Clamabantque, "Ruber Rudolphe magne,
Superstes tua fama erit per aevum!"
(Note: I previously announced both of these poems on this blog five years ago.) If anyone ever feels like arranging this, please let me know!
UPDATE: Commenter Joe Power points us to the Old English version about Hrodulf:
Hwæt, Hrodulf readnosa hrandeor --Click on the link for the rest of it, and the very amusing translation!
Næfde þæt nieten unsciende næsðyrlas!
Glitenode and gladode godlice nosgrisele.
Ða hofberendas mid huscwordum hine gehefigodon;
Nolden þa geneatas Hrodulf næftig
To gomene hraniscum geador ætsomne.