Idiocracy: Luke Wilson, Maya Rudolph, Terry Crews
Back To The Future: Christopher Lloyd, Michael J. Fox
I'm sure more actors could join this effort as well. Even though they were only actors, they got to study the theories of time travel and how events of one time affect future events.
I'm half serious here, if anyone can reach out to these former actors in the context of time travel, please toss them the idea of reaching out to the current world leaders (and even citizens), to point out how they're fucking everything up in a hurry, and more importantly how to start trying to resolve the problems...