What is there to do on a layover at Munich airport?
You’re right that Munich airport is a bit of a drag out of the city. It’s quite a dull journey on one of those trains that stops every five minutes. You should also be aware that security at Munich can be quite slow (though not been through for a couple of years). There’s an exhibition at the airport so you can learn about the new high speed mag-lev train they’re building which may mean you can do something more interesting if you come back in a few years. If you do decide to go into Munich can I suggest you get off the S-Bahn at Marienplatz, this puts you in the old town and will enable you to get a quick flavour of the town, maybe grab some German food at the Viktualien Markt and just have a wander through the older buildings/churches.