Subject: Why isn't there a highest possible temperature of matter?

I understood from various sources on the MADSCI website that there is 
no 'highest possible temperature of physical matter'. But when I was in 
highschool my Physics teacher told us younsters that the temperature of 
something is really just the speed of the particles inside that matter. 
Now if that is true, can it not be that there is a maximum temperature 
when the speed of the heated particles reaches the speed of light? Nothing 
goes faster than light, isn't it?

Re: Why isn't there a highest possible temperature of matter?