We live in Kaiserslautern and will have only 3 days to travel at Christmas. Does anyone have a recommendation? We thought of Munich. Will there be anything going on on those days or will it be closed down?

Awaiting your answers. We also will be there in the same time period. We assumed there would be little to nothing.

There is probably not much more activity in Munich than in Kaiserslautern on these days. You might find a nice Christmas church service on Christmas eve, with some good music if you are interestd in that. On the next day, you could take a day trip to Saalzburg or to one of the mountain resorts south of Munich. I'm sure it would be hard to find lodging in these resorts for just a few days, but you wouldn't have that problem in Munich.

>would be little to nothing
Correct, you can go to church at midnight.
After 1pm on 24th it will be dead, before that it will be the usual shopping nightmare. Buy whatever you need before 1pm, because after that the city shuts down.
Silent night...

PS: DON'T plan to DRIVE on Sunday to the resort(s); take the train, using the discounted Bayernkarte/Bavarian ticket . On the day after X-mas eve, the outbound roads from Munich are notorious for traffic jams. I'm sure, living in Kaiserslautern, you have heard about the famous German "Autobahn Staus". Well the A-8 and A-95 have the granddadies of all the Christmas Staus.

On the day after X-mas eve
Have Christmas turkey for lunch, then leave for the holidays Afternoon of the 25th is bad as well as the 26th.

Shopping nightmare downtown continues until new years eve, while driving on the Autobahn is rather relaxed.