Unfortunately it’s not in Amsterdam but De Pont, museum of contemporary art is worth the 1,5 hour trip with the train. The building itself is beautiful, it’s a former wool mill but also there collection is worth seeing!
The Bartolotti is perhaps one of the most beautiful Museum Houses Amsterdam has, built by someone who once was the richest man in the city, but it's a bit hidden in plain sight. These days, it is run by a group of lovely old ladies, who can't wait to offer you tea or juice. You can walk around the house like you live there.
You have to ring the doorbell to get in.
(picture from Google, by Arjan Bronkhorst)
Probably the cosiest place in town! Warm 'Berlin style' wallpapered living room build around a half circle bar. They host poetry, bingo & acoustic evenings in the front room, and great film, concerts and dress up parties in the hidden mezzanine back room.