Schlager is a form of music unique to German--it's its own genre. Comprised mainly of catchy tunes (that lead to ear worms), straight-forward forms and uncomplicated texts, you can hear Schlager at Oktoberfest, pretty much any Karneval celebration anywhere in Germany, and of course on German television.
You can easily dance to it and it's a good bet that you can dance with your kids to it and not worry about the texts.
A lot of Schlager shows are shown on TV in the evenings and are recorded performances in front of live studio audiences; and frequently, the singing is not live, it's lip-synced in-studio. I don't know why this is, but it happens all the time--even Nelly Furtado lip-synced one of her songs live on a German show.
Here's a great example of Schlager from Roberto Blanco, one of Germany's most well-known Schlager singers. "Wenn der Sommer erwacht" (When summer wakes up) from 2013:
You can even tune in to Schlagerparadies.de and hear Schlager music 24 hours a day! Need some peppy music to get you in the mood for your Kehrwoche? Or an upbeat tune to get you motivated to tackle your German homework? Try it out!