When women say that they want a guy that makes them laugh, it's practically a tautology: they want a guy that they want. They have the causality backward -- they laugh because they're attracted to him, not the other way around -- and probably most of them aren't even aware of it. Of course, laughter is only a sign of attraction if they're laughing with you and not at you, so the sign of approval elicited by clowning around is a fake one that won't lead anywhere.This is correct. And it's important to distinguish between attracted laughter and amused laughter. The former is when the girl laughs at anything an attractive man says and plays with her hair. The latter is when she's watching a comedian do standup.
The fact that a woman laughs at something Michael Macintyre or Frankie Boyle says does not indicate that she is sexually attracted to him. Nor will she be attracted to you if you manage to amuse her in some manner by your clowning. In fact, the genuinely funnier you are, the less likely it is that a woman's laughter means that she is attracted to you.