Hello, was in the same situation as you couple years ago, so here are my personal recommendations.
I can recommend taking a look into Rosenthaler Straße 39 and walking along Straße des 17. Juni. Maybe leaving a little autograph on the remnants of the Berlin Wall just opposite to the Mercedes Benz Arena. I can also recommend trying going to Curry 36.
If your class has to go to a museum, then the Spy Museum is the most fun, but the DDR museum certainly is way more interesting. Checkpoint Charlie is a must-go, but it can not recommend their museum nearby.
The absolute highlight for everyone was a tour around the Berlin underground, which was used by people to flee the DDR, but I think it is very hard to find a guide for it.
Nonetheless, just taking a stroll around Berlin is a experience of itself, as some places are just packed in culture and history.
Somehow “apolitical” people keep rambling about “The Left” and always praise right wingers.