can of corn

Etymology
The phrase, first used in 1896, makes reference to a long-ago practice where a grocer would use a stick to tip a can of vegetables off a high shelf, then catch it in his hands or outstretched apron. Corn was the best-selling vegetable and so was heavily stocked on the lowest shelves, making it the easiest of the can "catches" for the grocer. (See Seattle Post Intelligencer - Sports Answer Guy article)

Noun

 * 1)  An easily caught fly ball.