M_rk_s is right. Fun and funny have different meanings. Something fun is enjoyable or amusing. Something funny is comical and makes you want to laugh. Fun is normally used as a noun or an adjective while funny is usually only used as an adjective. (Fun can also be used as a verb and funny as a noun but people rarely do so in modern American English.)

Fun as a noun: "I had fun at the movie." - I had an amusing/enjoyable time at the movie.

Fun as an adjective: "It was a very fun movie."  - It was a very amusing/enjoyable movie.

Funny as an adjective: "It was a funny movie." - The movie made you laugh.

<em>Fun</em> is a noun and <em>funny</em> is an adjective :D

MOst of spanish speaking people I met they usually interchange this two words.

Fun - Amusing, entertaining, or enjoyable

Funny - it's an adjective words that describe anything that can make you laugh.

Yeah well, but that is not <em>just that</em>. Fun and funny have different meanings too. It's not just the noun and adjective form of one word. Comical and comics are adjective and noun too, but are completely different. Fun does not have to mean laughter. It can be 'general amusement' too. Funny does have to do with laughter. With jokes. Bromas!

Fun is a noun and funny is an adjective.Just that.