Can we create new senses for humans?

What non-human senses do we know of? From other species? It's been a long time since I was in biology class.

A lot of fish have that electrical field sense. Where they can "feel" the electricity from other fish. Obviously living in water is conducive to it. But who's to say that you couldn't "feel" the field from someone 25 feet behind you via air? It would be good for Marine Recon and ninjas.

And of course there's echo location. It requires two physical abilities: one a heightened sense of hearing and the other being able to emit the signals.

What else is there?

I'm not saying that we'd necessarily be limited to senses of which we're already aware. Or even to senses that already are. But the concept of "inventing" new senses... Wow. It would take someone far more imaginative than I. I mean give me ten million dollars and twenty-five mushrooms and I'll come up with something...

Anyone have any ideas?

EDIT: I guess I could have [followed the link and] watched the video before I commented. doh.

Anyone have any [further] ideas?