That would be Coffeeshop Splif:
http://www.splif.nl
It's on Koningstraat 8, just a couple of minutes walking from the trainstation.
When you leave the station, walk straight ahead, cross the street, keep walkin straight ahead (a park on your left, Rabobank on your right), cross the next street (called Breestraat), then the street diagonally to your right is the Koningstraat. About 50 meters or so on the left side of the street is the Splif.
Have fun!!