A few years ago, I found some good, dry fruit wood, and after borrowing a mitre saw, I cut it into lots of little medallions that were 3/4" thick and about 3-6" in diameter. After an hour of cutting, I had buckets of these little wooden rounds. I did not wax or polish them, just set them out for play and they made lovely free toys.
We still have many of these loose pieces around our house that are played with in all sorts of ways (as cookies, coins, cutting boards), but I was inspired to make a toy tree house after seeing some beautiful examples online (especially here and here).
I carefully cut some branches to make the vertical supports, trying to keep the two cut ends parallel to each other, and then started building stairs from the ground up, using the small wooden rounds and a hot glue gun. (I highly recommend hot glue for this project; it dries quickly, and is very forgiving of uneven and not completely parallel surfaces.) I started with one spiral staircase around a column, and then kept adding more parts to go with the set.
On one tower, I added a railing made from a pine cone and some beach stones, as well as a rope ladder tied to two small holes that are drilled in the floor of the turret:
We have added new elements to this play set again and again, including a magnolia branch in plaster found at a yard sale (perfect for the basket lift), some cool old wooden finials from a broken headboard, ramps and ladders made from popsicle sticks, little wire chairs and a tipi.
Parts or all of this set move from table to floor all around and outside of our house, and I have needed to repair it a few times, but it has always been easy to mend with hot glue. It has seen many hours of play, and is frequently inhabited by kings, pirates, evil-doers and acorns.
(Click on the pictures to enlarge)
If you are inspired to make one of your own, please put a link in the comments or send me some pictures!