Taking a cue from America's ubiquitous concrete parks, Amsterdam now has its own Marnix Bowl, so-called (duh!) because it's set in a pretty neighborhood park on Marnixstraat, on the western edge of the Jordaan. On a fair day, you'll find skateboarders and BMX-ers practicing figure eights, pumping the corners at speed, and doing fluid transition laps on the smooth concrete.
Naturally, the entire bowl is covered with colorful graffiti. What else would you expect at a public park in central Amsterdam? Entry is free, as is access to the adjoining basketball court, children's slide and climbing equipment.