This cartoon by John Darkow from the Columbia Daily Tribune is another example of the driving/running off the edge of a cliff idea, which I looked at in a previous post. In this cartoon we see President George Bush handing the keys of the car to Barack Obama. The car represents the U.S.A (note the numberplate). Bush says: "Here's the keys, Barack; you'll notice they're in excellent condition!" The joke is that the keys may be in excellent condition but the rest of the car is falling apart (and going over a cliff!) The cartoonist might also have been thinking of Barack's new armour-plated limousine, nicknamed "The Beast".
Of course, Bush should have said "Here are the keys", but grammatical correctness never was one of his strong points. In his defence, many people do use "here's"—and "there's"—before a plural noun, especially in spoken English. Language Log has a detailed discussion of this usage.