Unfortunately, bicycling isn’t all that great here… unless we build a trail first. Hmmm that’s an idea! As it is, directly behind the house is a big gully, with the creek running through. Makes for a stunning view, but it’s pretty much unnavigable with a bike. Up on the other side is many acres of ferns and woods. Wonder how hard trail building is?
Big gully - how deep and wide is the creek? My siblings and I whiled away many hours in the one that runs through the 'rents yard, building log and stone dams that washed away next high water, dunking each other in the resulting pool, and making then racing woodchip boats.
All you need is a creek, two hammers, lotsa wood scrap, and even more finishing nails. Get as elaborate as you like, we certainly did - anchors, deck cabins and everything.
If its too fast/deep/wide, you can play Poohsticks (tricky without a bridge, but a little imagination provides alternatives).
Go out with a plant identification book, and set little scenarios like oooh, throw a rock and have the kids look for as many edibles/flowers/weeds/whatever as possible within five feet of the rock, with a candy or something as a prize for the one that finds the most. (Little plastic whistles that must go home with the children, don’t you owe your brother a little extra? )
Building a biking trail from scratch didn’t seem that hard exactly, but it involved more organized effort than us kids wanted to really go for. Grubbing up wild rose bushes is painful work. And it took a week of said work to make the trail usable. Much much easier to modify existing footpaths/animal trails, if any. IIRC, if blisters and sweat are involved, there better be major fun of some kind happening around it.
Or at least that was my take on the building a bike trail. Takes too long and involves too much Real Work.
However, building a toboggan run is Way. More. Fun. Takes just one day (depending on the snow, and how many motivated bodies there are) to make a winding trail and bank the corners way up. If feeling especially daring, dampen the run. WHEEEE!!!
Marbles are still cool, according to my kids (grades six and eight), although they are overruled in coolness by Dragonball Z.
Anyways, that’s apparently all the top of my head contains at the moment.