Replying to Fresh water surfing?

ok so after coming across the big ol waves on lake superior thread, it got me to thinking, is there really a fresh water surfing scene?  call me ignorant if youd like, but ive just never heard of such a thing! 

now i know that large lakes end up with tides thanks to our moon up dare, but i didnt know they offered surfable waves!  this is bonkers to me, and again, i apologize if im just a goofball and dont get out enough.  regardless, my mind is blown.

and another thing...do these big ol lakes freeze all the way over in the winter?  like could i ice skate a hundred miles across lake huron or something?  i gota get to the midwest, this whole thing is just zany to me.

somebody out there, just let me know the scoop, this is like a preview of 'how its made'...i need to know how these bid ol lakes work!