Most of us know it - that weird, sudden feeling of experiencing something not for the first time. It's called déjà vu - French for "already seen" - and it's an uncanny feeling. But according to new research, that's all it is. Just a feeling. The most accepted explanation is that it has to do with memory. Much like a word can be on the tip of your tongue, a memory could be on the tip of your mind - there, but not quite accessible. Jeff and Anthony think they might have done this story before.