I feel like we can all just jump at the same time. I mean, we only need a second or two, right?
Well...we would all have to be at the same spot so that we don't cancel each other out. But that would come with its own challenges
(oh and it wouldn't be strong enough to affect the Earth's rotation)
Maybe a whole bunch of people can charter some planes, fill them with weight, and just travel full around the earth to where they started.