I had to look into Wikipedia to get real name for the hat (it's called "cylinder" in russian) and I still might have some parts named incorrectly - english is not my native, it's also my first instructable so please don't judge too hard. I'll greatly appreciate all corrections.
Step 1: Get playing cards and stapler
The fastest way is to go to closest pharmacy - they always have different decks for sale (for some reason I like classic Bicycle decks for these projects).
You can also buy decks in bulk in your closest Costco, BJ's club or similar.
Most popular decks have red or blue backs and regular pocker faces but if you have some special project and you know where to look, you can find black backs, white (yes, empty) faces or even some colored ones.
As for stapler, you can buy the simplest one as I did or go for signature staplers like this red swingline stapler from Office Space movie.
Step 2: Attaching cards for the top
First, we want to make a top of the hat so we need to attach cards in a line long sides next to each other.
- Staple two cards overlapping them just just enough for one staple (you can quickly measure it by aligning one card to touch the circle on another card). Just staple them next to short side of a card.
- Check the other side to see if you stapled through both cards
- Keep stapling them to make a line of cards (amount of cards depends on a size of the target head - I got 15 and it was a little bit bigger then needed).
- Staple the last card to first one and try it on your head - it should fit relatively tight).
Step 3: Finishing the top
When done adjusting (it's important step - it'll be too late when you have whole thing done), remove one staple getting it back to flat form.
Then get a ruler and use it to bend a edge of the cards up. It doesn't really matter how much you'll leave for bending - it will only affect the size of the ventilation hole in the middle.
Now, when you bent the whole thing, you can connect last and first cards together to see how it'll look.
Step 4: Attaching brim
Maybe it's better to do both sides simultaneously saving on staples and making the edge a little bit more neat but it's harder to handle when bending so you can try it with your second hat.
Keep stapling until you get whole line of cards finished. Keep in mind that you'll have last card shifted the same direction first one was.
Step 5: Add some height
It doesn't matter actually how many rows you put and if you attach long or short sides of cards.You can also shift next row against previous to make pattern more interesting. You can use one row of staples or do double rows. You can have additional inner layer of cards face to face with outer layer to make inside colored and so on - feel free to improvise.
When you're done with second row, attach them to make a cylinder - it'll be much harder to do when you have third row (depending on the size of your stapler of course)
Now try it on and make sure it fits exactly as you want it - it's still not too late to adjust the size until we get to making brim.
Step 6: Staple top cards makng the ventilation hole
I used special (tiny) stapler to do this but with some practice you can do this with a large one too. Just staple through cards - the more staples goes through cards the stronger hat gets.
Step 7: Make holders for the brim
Staple cards that match bottom color you planned for the brim with faces into the hat, one half overlapping the sides, shift this raw against the sides for a half of the card.
Then cut outstanding parts of the cards into halfs with scissors and bend them out so they spread out evenly. You can probably cut them into three parts to make an edge more round and smooth but you'll have to do more stapling later and that's a lot of staples ;)
Step 8: Top layer of cards for the brim
Now attach top layer of cards for the brim by stapling them to the folded out half-cards you made in a last step.
Make sure they aligned radially and not skewed left or right. Overlap cards to cover about hakf to 2/3rds of previous card - we need relatively smooth edges. Be aware that brim takes most cards and it can make hat havier if you overlap too much or less strong and less neat if you overlap too little.
Also make sure you staple through the cards on the bottom - this will give brim needed strength.
You might want to shape it into oval to match the form of your head. I didn't try it but for better results this step be better done while target wearer has it on. Be careful with ears though - staples are sharp ;)
Step 9: Adding bottom layer of cards
BTW, Here you might want to use pliers or something similar to flaten the staple so they don't bother you that much when you touch them.
When you're done attaching all cards (remember, last card should go under first one), do another round of stapling closest to the sides of the cylinder having flat sides of staples towards the bottom of the hat - otherwise ends of staples will give your hair a hard time.
Step 10: First one done, make them for all your friends and family
Don't be afraid of improvising with sizes and colors.
When you're done, make another one for you friend, put them on and go to a party - others will just die of envy.
Hope you enjoyed the process.