Pig bladders were washed and dried for a variety of applications.
When glass was expensive and rare were (sewn together) bladders used in windows (as glass). (Besides oiled paper and canvas, which also let in light and stops wind.)
vakensblaasvoetbalShe served as a tobacco pouch.
Are still used for lampshades.
They were blown up and used as a (not quite round) football. Later there was a leather outer ball around.
They are also used as a covering for a tambourine or drum, or blown up as a sound box for a one-string violin (bladder fiddle).

A very well known folk instrument was the friction drum called tens of names in different areas.
The bladder is dried first a few weeks, until it got a parchment -like consistency. You press a (litlle) stick in the middle of the surface, and bind the bladder a few cm above the (thicker) end tightly around the stick. With the stick up, tighten your bladder over the edge of an earthenware pot, and tie it around the jar tightly. (In some versions there is made a hole in the bladder ​​where the stick goes trough.) By the tension the stick in the middle remains upright.

If you rub (with wet hands) on the stick, vibrations are amplified by the membrane and the pot into a characteristic, humming sound.
(It can also with the skin, instead of bladder, and even with a plastic bag over the can.)

Bladders and stomachs were also used as a cooking pot. In her book series about prehistoric Ayla, Auel gives descriptions.
By binding a vertebra in the opening you can close the gap with a stop.
A cooking bag you put in a (clothed) hole in the ground. You fill the bag with water (or soup, tea...), and put some bones on the bottom. Then you put in the fire heated stones into it with a rod or forked branches. The bones prevent that the skin burns. Because of the heat goes into the water it boils. Possibly you have to replace the stone several times with hot ones from the fire.

In the kitchen, stomachs and bladders are also used as coatings for food. You can e.g. also make (blood) sausage in them. Dishes vary by region, what is available is put into it. E.g. cut into cubes meat, potatoes, bread, spices and milk. Add e.g. also peppers, and you get yet another typical regional dish.

The woman who thinks that the love of the man goes through the stomach, is aiming too high. (?)

Knucklebones is an old folk game. The ankle bones of a sheep leg were used. But it can also with other small bones. Or stones.

The players sit in a circle, and try to go as far as possible to get a fixed set of figures.
Four dibs lying on the ground. The fifth is thrown up, take with the same hand another dibs on the ground and immediately catch the falling one again in the same hand. So you pick the four apart.
At the next set of figures you pick up the knucklebones per two at a time, then a third, and them all.
Afterwards you can further vary by catching the diced dibs on the back of your hand. Then, 2, 3, 4 and 5. And then you pick the knucklebones after first popping them under a bridge, made ​​by the thumb and fingers of your other hand on the ground. But that is for experienced specialists.