How do you use this part?

Because many of us would like to learn how to effectively use more of the parts in the NXT kit, I'm going to start by asking you, our readers and bloggers, to share how and when you would use this part---the TECHNIC Knob Wheel. If you include pictures (which I hope you will), please make them close-up shots.
Comments
They are very useful and can be used as normal gears.
As for pictures, I used knob wheels in the feet of the biped I posted earlier. I used them to make a 90° angle, like Philo described.
They are more reliable than the black bevel gears in the kit when there is a heavy load on the gears, like in the biped.
Sumo video with knob wheel in action
Also have a look at the comments from a previous post here
Back in the old RCX days we used those as part of a homemade rotation sensor. The knobs are perfect for pressing the button on a touch sensor and you got 8 counts per revolution. Half as good as the rotation sensor.
Now leave me alone you whippersnappers. I'm going to take a nap.
For example:
Pieces are listed by name with a picture ( having it in the forum lets anyone post a picture).
I'd also like to see multiple pieces snapped together an a useful configuration , given a meaningful name, compared to a real world mechanical configuration....
To date, I haven't seen anything like this for technic pieces.
TOUCH SENSOR? You were lucky to have a TOUCH SENSOR!
Luxury. *grmbl*
We had to build our own touch sensor with filthy cracked LEGO beams cut out from a brown paper bag with LEGO advertising on it.
Which we got for working twenty-nine hours a day down mill and pay mill owner for permission to come to work!
But you try and tell the young people today that... and they won't believe ya'.
I added a closeup shot to your forum entry.
see:
http://thenxtstep.com/smf/index.php?topic=263.0
David