Not a big fan of zoos and animals behind cages, but if you can spot Flamingos in the east-centre of Amsterdam, then count me in <3 ! You can actually see them while riding the bike on Plantage Middenlaan, quite a beautiful scene.
Note: De Plantage next to zoo is quite cool cafe/restaurant, with a mix of vintage style and industrial elements of the old buildings of Artis. Great atmosphere, and ideal for a more sophisticated outing.
Hidden in the greenery near Westerpark, the perfect hideaway from street noise can be found if you know where to look: a little farm called "De Buurtboerderij". Surrounded by a bunch of sheep and a happily decorated garden, the restaurant inside serves one fixed menu a week for a low price. The farm serves as community center as well and is run by volunteers — and you when you eat there! — and there are plenty of sweet people and animals to hang out with.
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 :)