How small do lenses get? (ex- 50mm 1.8)?

My nikon AF 50mm 1.8 is pretty small for a lens (http://kenrockwell.com/nikon/5018daf.htm). Its the smallest lens I've ever seen, but I'm new to photography.

So my question is - how many other small lenses are out there? For Nikon or Canon. I think its nice to have things small and compact. I know that the more important aspect is image quality, etc but right now I'm just curious about size.

oh and btw, no lens converters!

I know that there are PLENTY of 35mm prime lenses (Canon, Nikon, etc.) Check out this 25mm Olympus prime: http://www.pixelthingy.com/lens/overview/1752

I've had 28mm before.

If you had gone with an m4/3 camera (Panasonic G1, Olympus E-P1 etc.etc.) you could use Pentax 110 lenses, these are tiny, but work superbly, they don't have any aperture adjustment and they are all f2.8. Here is my Flickr photo-stream showing sample images and the adapter I designed to get around the aperture restriction.

These lenses are available from around £10 on eBay.

The Canon 40mm "pancake lens" may win this award. On a big DSLR it's almost not there, link

Small how? The smallest f~stop? The dimensions? The focal length?

be specific…

Tamron makes an 8mm-16mm lens, I have seen a lens with an f-stop of 1.2 before… Please be specific… How do you determine a lens to be "small"?

Most manufacturers make a smallish lens, some call them 'pancake' lenses. But really, if you have a SLR body, that in itself is not small.