If you're looking for a bit of the Christmastime cheer but not feeling like trading ROMs to switch to EVOZone's Christmas ROM, then you should know that developers mayfield103 and eg1122 have released a massive Christmas theme to decorate your GSM or CDMA (Sprint) HTC EVO 3D.
X-Mas Sense 3D, as it's called, features red and green keyboards, many icons turned into ornaments, icons with Santa hats, Santa icons, Christmas docks, themed clocks, and tons of details everywhere.
It's a theme, so you flash it in recovery. And as with any theme or root item, you should make a Nandroid backup first in case your phone decides to Grinch out on you.
There are a couple of minor issues reported with certain ROM combos, but nothing too major. For example, there's a screenshot issue with Warm ROM (with a fix on page 12 at the link below) and a status bar issue on first boot with Clean Zrom that goes away after a reboot. It's basically nothing terrifying.