Two blondes fell in a hole and one asked, "It's dark in here, isn't it?" and the other one says, "I don't know, I can't see."
Blonde in a Hole
Explanation
This is a classic "blonde" joke that plays on the stereotype of blondes being a bit ditzy. The humor comes from the second blonde's silly response, stating she can't see when that's the reason they are in that situation. Basically, she didn't understand the question or the situation.
Anonymous
Maybe she was blind...