Conservation of Energy and a giant pendulum:
Well explained and stands alone well.
Oil Slip & Slide:
Even really slippery surfaces have a coefficient of friction that slows down moving objects. You could have students estimate it using the values given in the clip.
LN2 filled water bottle:
Quick example of pressure, boiling and of course liguid nitrogen.
Does a duck's quack echo?
Sometimes students just won't believe you unless they see it for themselves. Or in this case hear it.
Don't microwave a CD:
Playground G forces:
Brainiacs (the volunteers and staff that put on the science of the show) try to get the most G forces possible out of a playground merry-go-round. You could get more but they are limited by human power.
Iron in cereal:
This is an easy demo to do in the classroom but it does take some prep, the right cereal, etc. This is a super short clip that demonstrates it if you don't have the time.
Now I want to watch more of it. Besides the energy pendulum the only other clip I have seen prior to this was another all time favorite, "The Electric Fence." It is pretty much all the things you wish you could do in your classroom but couldn't:
Update: For an exhaustive video demo lesson on the Brainiacs: Electric Fence clip, see this old Blog of Phyz post:
Electric Fence Redux