The Russian cast off (Russian bind off) is a looser, stretchier and more elegant way of casting off than the traditional method. It works particularly well as a finishing to ribbing, especially on a ribbed collar or a ribbed band (eg on a hat).
To start with, take your row of stitches (practice on a swatch first I think)
Knit the first one as you normally would when casting off
Now, insert the left needle in the back of the stitch you just knitted, you should have this sort of thing...
Now, take the tip of the right needle and insert it in the next stitch, as if to knit,
you should see a lovely cross formed with the stitches and the needle through both of them and out the back, like this
Now, just pass the yarn round the needle as usual for a knit stitch
Pull the point of the needle back through your cross, you should have a lovely stitch on your needle
Now pull that off the left needle, and start again
Put the left needle through the back of the stitch on the right
Right needle through next stitch to knit
Keep going, it should look like this
and eventually, you have this
Here are a couple of examples of this stitch in real live action.....
The collar of the Drops Jacket
The band of the Astrum Beret
Simple, elegant and useful, give it a go.