The city's biggest flea market is hosted the first weekend of each month in and around a gigantic warehouse in the industrial area of NDSM in Amsterdam Noord. I love to snuff around the hundreds of stalls to find unusual props. Taking the boat to cross the IJ and leaving the old centre behind is very refreshing. Make sure to also have a drink in Noorderlicht while the sun sets.
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.