Beautiful and well-marked trail with amazing views of Zugspitze and the Alps. It's a steep climb, but not too difficult. The trail is popular with locals and quite busy, but definitely not overrun like the trails on the opposite side of the valley. Along the way are a bunch of alpine cabins & farms offering Bavarian food.
Another plus is that this trail is easily accessible by public transport, e.g. from Munich. Just take the train to Garmisch-Partenkirchen (approx. 1h) and walk from the train station to the trail head.

Best 4 Euro ever spent! The rocks are a little slippery but the adrenaline rush is

This is a great hike, but it's not a moderate one unless 700m of elevation change and a rather steep 15 min via ferrata climb at the end is moderate for you. Children must be experienced to enjoyably make this trek and a safety harness is probably a must for most children. The 360 view, though, is worth the 4+ hours roundtrip to complete this climb.

This is a really cool area in Berlin, and you'd be crazy to miss it. During the day you can see some of the remnants of the wall and explore all of the different cultural buildings (museums, opera houses, philharmonic) nearby, and at night this place is buzzing (especially the Sony Center). If you like people watching, go to the Sony Center.

They also have a spectacular Christmas market (as do many places in Berlin), complete with a snow hill to tube down and an ice rink (don't drink too much Gluhwein before attempting these).