Backwords (Backwards words) is currently trending on youtube. It's also a very simple and fun up front game.

Supplies:

Recording Device (I use an iphone)
Software to play the noise back in reverse (I use an app called backwords)
A Speaker to connect to your playback device (I use a portable speaker w/headphone jack)

How to Play:

Have two people come up front. Give them each the same word to say in reverse. For example... "trash can" backwards would be "nac hsart." Have them say it backwards while you record it. Then play it back to the crowd in reverse and vote on which contestant's word sounded most like the word they were attempting to say. Here's a good video to help you understand. Some of my students watch these youtube videos for entertainment... so they'll definitely be entertained when it's happening live.

Here's a video so you can get a better idea of what the game is like (we had to change it after the first video was set to private so disclaimer: I didn't watch the whole thing, it might have inappropriate parts but it seemed cleaner than the others ones. You can youtube backwards word challenge and see other similar videos).

Use themed words to make this appropriate for any Holiday event.