The phrase ""Boil The Ocean" describes an attempt at something that is way too ambitious, effectively impossible. The first time I heard the term was several years ago from an IBM developer. I thought it was an IBM-ism but I've been hearing it more and more outside of IBM. A Google search turns up an early use of the phrase that really captures its meaning:
When asked by a reporter what to do about U-boat sinkings during World War I, Will Rogers is said to have responded: "Boil the ocean". "But how would you do that?" the reporter continued. Without a beat Rogers replied, "I'm just the idea man here. Get someone else to work out the details."
Classic.