John Baez has an interesting webpage about them

 

http://math.ucr.edu/home/baez/subcellular.html

 

This includes things much smaller than usual virus including Spiegelman's Monster which is only a couple of hundred base units long.

 

At the other extreme there is this virus which is bigger than a lot of bacteria. So big that for a while it was not even recognized as a virus.

http://www.livescience.com/animalworld/041111_giant_virus.html

Cool.

 

I often wonder if non living material, like simple and complex polymers, and even some inorganic material in our internal and external environments, play a much larger role in who we are, how we thing and behave, and how we adapt and evolve. Like aluminum and PCBs and stuff. Or maybe I'm just getting pissed off because I'm growing old and losing my mind and growing man breasts.

Prime-Evil.

Don't know about non living material. However, certain viruses have now been associated with some psychiatric illnesses. I suspect that we are due to discover a large number of viruses that inhabit the human brain, and cause all sorts of interesting behavioural changes.