Sail the IJ Ferry
The short free ferryboat ride across the IJ channel between Centraal Station and Amsterdam-Noord (North) is a great micro-cruise that affords fine harbor views.

View Golden Age Paintings
Usually it costs a bundle to see paintings from the Old Masters period of Dutch art. A free exception is the multiple images of Civic Guards (Militia) companies hanging in the Schuttersgalerij of the Amsterdams Historisch Museum.

Visit the Begijnhof
Even though admission is free, there's a price to pay for stepping into the cloistered community that for centuries has been a residence for women of "sound character." You need to be tolerably quiet and comport yourself with dignity -- or you'll get tossed out by the guards.

Visit the Flower Market
The vast array of flowers and potted plants in their "floating" home on the Singel canal comprises the city's largest and most colorful plant assortment. However, purchasing the flowers is not free.

Take in a Lunchtime Rehearsal Concert
If you can live with the occasional duff note and a program that doesn't always follow the script, treat your ears to classical music from 12:30 to 1pm at the Muziektheater (Tues) and the Concertgebouw (Wed), every week from October to June.

Stroll through Vondelpark
Its 48 hectares (120 acres) of trees, ponds, flower beds, and picnic grounds comprise the city's green lung -- even if the fresh air is often spiked with marijuana smoke. In summer, concerts and all kinds of open-air activities take place.