Read this essay. It's awesome.
It basically details a theory that Rickard Stark had planned to overthrow Aerys or force him to make changes to his regime before the tournament of Harrenhal and after the war of the Ninepenny Kings.
The basic evidence is in the fact that major houses were betrothing their children to each other when that was an uncommn practice. If you look at the wives of all the major Lords (Stark, Tully, Baratheon, Arryn etc) they all married women that were bannerman to their state. Suddenly Starks are betrothed to Baratheon and Tully. What would be the purpose of these marriages?
This guy believes the purpose was to join those 4 houses together to end Aery's reign over the 7 kingdoms.
Read the essay, it's long but it makes a ton of sense.