“Fun” is different from “funny”. “Fun” is something that is enjoyable in the sense of an activity (es divertido en el sentido de entretenido). “Funny” is what you may say about a joke or the behaviour of Mr. Bean (a diferencia a “funny” que es divertido en el sentido de gracioso).

Some examples:

• Shark fishing is fun (…es muy divertido).
• Mr. Sanchez is not much fun (no es muy divertido).
• The party was fun.

Now some examples with “funny”.

• • That is not funny (eso no tiene gracia).
  • You look so funny in that hat (tienes una pinta graciosísima con ese sombrero).

Sometimes you may use “funny” satirically (satíricamente).
When Mrs. Margaret Thatcher, the acclaimed (aclamada) British Prime Minister, said – at the time of her resignation – that it “is a funny old world” she meant an odd or peculiar (raro o extraño) world.