Imagine you are standing on a long beach. Imagine a bird flying into the coast and picking up a grain of sand before flying away. A million years pass before another bird comes, takes a single grain of sand, and flies away. Another million years pass. A bird comes. One more grain disappears. The cycle continues. However long it takes for the beach to be completely cleared of sand is what infinity is.
(As remembered through the telling of Christy Salley).