I have a hard time with just sitting doing nothing in waiting rooms, in meetings, riding in the car. It seems like my hands should be busy, you know? So I'll bring along a little portable project. Folks are used to seeing knitting or crochet...but I have a tendency to bring my drop spindle, lucet, or kumihimo. Kumihimo is a form of Japanese braiding, and has been my current favorite for a portable project. I get lots of questions on what I'm doing. It looks so complex, but the process itself is so simple. Here...I'll show you the pattern I've been working with recently.
First, you need something to hold the threads as you're working. You can get a braiding stand called a marudai, and real tama (bobbins) for your thread. Or you can make your own cheap and portable substitue. Go get yourself some craft foam from your local craft store. I found some that is thin, but has adhesive already on it. I stuck three layers together, then cut out a circle around 4 1/2" in diameter. I cut 24 half inch slits in the edges, evenly spaced around. Then I punched a hole through the middle. There. Marudai made.
Now, find something to wind your threads around. I use knitting bobbins. You'll also need a weight on your finished cording. I use an old fishing weight, dangling from a paper clip. Measure your threads. This last batch was I think 5 times the distance between the arms of the chair I was sitting on at the time. Wind them on to the bobbins, knot the ends together, and shove the knot through the hole in the middle of the foam. Hang your weight from the knot. Arrange your threads in opposing pairs the way they are in the first picture here. Hold the foam in one hand, and let all your threads dangle below. There! You're ready to braid.
I was taught this particular braiding pattern with the mental reminder, "LEFT UP to me it would be DOWN RIGHT fun". To unpack that a bit: look at the pair of threads that is in the 6 o'clock position in front of you. Take the left most thread, and move it up to left of the pair of threads in the 12 o'clock position on your board. That is the LEFT UP move.
Now, take the right most thread in the 12 o'clock position, and move it down to the right of the thread in the 6 o'clock position. That is the DOWN RIGHT move.
Rotate your work counter clockwise, to bring the next pair of threads into position.
Repeat the sequence. LEFT UP...DOWN RIGHT...ROTATE. Keep repeating.
This pattern gives you a round spiral braid. Experiment with type and color of the thread you use, and the starting position of the colors. The same sequence of moves can give you quite different looking results!
Give it a try sometime! Let me know if you have any questions. There are also some very good books on the subject. I can recommend "Braids" by Rodrick Owen as a good one to start with. Good luck!