Billionaires, tech CEOs and top members of the Republican establishment flew to a private island resort off the coast of Georgia this weekend for the American Enterprise Institute's annual World Forum, according to sources familiar with the secretive gathering. The main topic at the closed-to-the-press confab? How to stop Republican front-runner Donald Trump. Apple CEO Tim Cook, Google co-founder Larry Page, Napster creator and Facebook investor Sean Parker, and Tesla Motors and SpaceX honcho Elon Musk all attended. So did Senate Majority Leader Mitch McConnell (R-Ky.), political guru Karl Rove, House Speaker Paul Ryan, GOP Sens. Tom Cotton (Ark.), Cory Gardner (Colo.), Tim Scott (S.C.), Rob Portman (Ohio) and Ben Sasse (Neb.), who recently made news by saying he "cannot support Donald Trump."