When in Amsterdam, do as the Dutch do and rent a bike. There are half a million bikes in the city, so be sure to look both ways before crossing the street!
Bike rates average 12 Euro/day or 50 Euro/week.
Mike's Bike Tours (www.mikesbiketoursamsterdam.com) offers four-hour tours in Amsterdam or in the countryside (think windmills, tulip fields, cheese farms), all suitable for kids and adults.
MacBike (www.macbike.nl) also provides good rental options and offers themed rides focusing on architecture, canals & bridges, Jewish Amsterdam, Windmills & Rembrandt and more.