There is a wide and interesting variety of spending freetime in and around Kalkar.
You can walk through and around the historic part of Kalkar (which feels like living in the middle ages yourself),
bike along the "via romana", a historic roman road, fly a glider, spend your days at "Wisseler See", a nice lake with a beautiful landscaped recreation area,
thrill yourself at "Freizeitpark Kernwasserwunderland" (a fun park build in a never used nuclear power station nearby),
guided sightseeingtours, visit different historic places from the roman period and the middle ages,
visit great museums, take part in cultural events.