Extreme knitting is knitting on very large needles: both very thick:
and very long:
One form of extreme knitting is giant knitting. This generally involves giant balls of giant wool:
This is used to make housewares, including mattresses and blankets:
rugs, futons, pouffes:
and, uh, clothing….
You can use these yarns for arm-knitting too, but that’s a different topic.
You can, of course, use these huge needles with finer yarns: it produces a lacier effect. Here’s a video showing how to knit your own hammock, suspended on giant needles:
The other main form of extreme knitting is multi-strand knitting. In this, multiple balls, skeins, hanks of yarn are worked together as one – again on the giant needles. Here’s Rachel John knitting a mattress with 1,000 yarns on a pair of sharpened trees:
A third form of extreme knitting gets very little press. Extreme miniature knitting:
The image above is an Aran vest by Althea Crome, the designer for the movie Coraline. She produces 1:12 miniatures on 0.25mm diameter steel pins, using fine silk embroidery thread at around 3 stitches to the millimetre (80 sts/inch)!! OR LESS!!!
And know there are people working at smaller scales…
Quora linky.