To get out of the hustle of the city, my husband and I love to bike down to Amsterdam's Forest to see the goat farm, or picnic in the sun. There are also little spots to swim :)
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)