One of Nijmegen's lesser-known secrets is that there's a glider airfield about 5 km south of the city border. Technically, that puts it in Malden, but they still call it the Nijmeegse Aeroclub. On nice days, if you remember to look up, you'll see the gliders circling the thermals in the skies towards the south. There will usually be 3 or 4 of them at the same time, just lazily winging through the skies.
It's relatively easy to get to by car and bike. On the weekends, an ice-cream truck stops and sells ice cream out the back. But the main attraction is that, at one end of the airport, there are benches and tables, and you're allowed to watch the gliders take off and land. Watching them take off is a real treat: the winch truck revs up its engine, and at the other end of the field, you can watch the glider rocket into the air and, on a good day, catch a thermal.
Kidlet loves planes, cars, trucks, trains--anything motorized, essentially--so a lazy afternoon watching the gliders take off and land, while riding his "new" loopfiets (it was a present when he was born, but he only just started riding it this week) up and down the dirt paths, being a kid and every now and then yelling "PLANE!" was about as perfect a day as it could be.