We all know about the story of the tortoise and the hare, right? So how about a twist on that for an ad for Rogaine called: "The Tortoise and the Hair"? The ad could say that the tortoise's love life was slow because he was bald, but then he used Rogaine, and he got this great head of hair, and so now he's winning, and his love life is fast. And for an extra joke, he could be dating rabbits, because of the original tortoise and the hare reference, and also because of something else people generally think of in reference to rabbits, which might be an extra incentive for men to want to have a full head of hair. (All these ads sell this kind of stuff this way.)
The really fun part of this ad would be showing some tortoise with some hair metal band hairdo or something. That would look ridiculous!