It's called a Mystery Braid Bracelet! Check it out:
I kinda don't want to tell you how it's made... cause it's SO easy and you won't think I'm cool anymore. :oP Here goes!
You can get the leather bracelets with the slits from Michaels (I heard Hobby Lobby has 'em too.) Don't forget to use a 40% coupon. My pack was actually labeled "Mystery Braid Bracelets" and came in a pack of 8. There are some "flakey" bits in the package (like dots?) but over all I think the quality is nice! It says "real leather crafts" and it feels like it.
The package comes with these directions:
1) Pass the bottom end of the band up between strands 2 and 3, and push the resulting twist to the bottom.
2) Begin braiding by passing strip 1 over 2, then 3 over 1, then 2 over three. Pass the bottom end of the trip between 2 and 3 then work the braided portion up to the top of the band. This completes one braid cycle.
Then you basically just repeat!
Here is a pretty good video (from the company that made the bracelets) with the instructions. (Had a bit of trouble embedding it, so you'll have to view it on YouTube).
Then you rock your bracelet and make them for everyone you know cause now you have 7 extras. :)
I discovered you can make a tighter weave or a looser weave based on your preference. It's just a matter of doing another braid cycle.
Tighter weave on top, looser weave on the bottom
The light brown and medium brown leather straps were a lot more supple than the dark brown, so it was easier to do a tighter weave on those. Another thing to consider is that the tighter the weave, the tighter the strap, so if you're making it for a person with a bigger wrist (namely guys), it might be better to go with the looser weave if you don't get to measure them in person. If you do the tighter weave and need to make it looser, you can always undo it! :)
"Though one may be overpowered, two can defend themselves.
A cord of three strands is not quickly broken."
~ Ecclesiastes 4:12 ~