It's so funny that this thread caught my eye tonight! I was on a money-saving forum yesterday and saw a thread where someone was asking about what the cheapest to care for pet was and immediately I just had to reply, "A pet rock!" hahahahaha!
I actually bought in to it sort of when I was a kid. My parents wouldn't let me have a pet for the longest. (They finally caved when I was 8.)
We went to some sort of arts and crafts festival when I was really young and they had given me some money to shop with. I remember spotting a booth where a lady was selling rocks decorated with fur and bows or little handmade outfits and googly eyes glued on. I just HAD to have one!
I passed it on to my now 11 year old daughter when she was 3 and she still has it as well. She actually has a rock collection, so it is very funny to her.