I'm new to Ruby with PHP background.

* Is there any super easy explanation or tutorial for proc and lamda?
* Do I need experience with Lisp or Smalltalk?

Proc and lambda are most fun part in ruby, people say. But, I feel I'm
dumb. I read the Pickaxe book, but couldn't fully understand the
concept. I don't have to be able to use them soon, but I at least need
to comprehend them.

-J