You won't be able to get a taste of Gears of War 2 without ponying up the cash: No demo of the soon-to-be-blockbuster will be released.
"[There are] no plans for a demo," associate producer Tanya Jessen told Shacknews. "The reason being that it's been such a fast turnaround. A two year production cycle, for a game of this caliber, is really short."
The first game did pretty well without a demo, BTW.
ShackNews: No Gears of War 2 Demo Planned