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.
OT301 is a cultural centre in the former building of the Film Academy at the Overtoom. It’s a good place to get drunk, watch a movie or to eat. It's not too expensive, like most other places in Amsterdam, and the ambience is good.
Jenever is a traditional Dutch spirit, sometimes called Dutch gin or wodka in English. Wynand Fockink has a distillery and tasting house right at the very hart of Amsterdam. This place is frequented by locals and tourist alike because of their delicious jenever. Be sure to try a glass of Wynand Fockink Superior. If they empty the bottle while filling your glass you're entitled to a so-called 'Amsterdammertje'; you'll have to drink your glass in one gulp and then you get a free refill.