1. That sounds fun to me.

Question

(What is the part of sppech of 'fun'? Is it a noun or an adjective? What about "funny" instead of "fun"?

2. That sounds funny to me.
3. That sounds interesting to me.

(Do the three have the same meaning?)

Answer 1

The word "fun" is essentially a noun, but in informal English is also used as an adjective:
http://www.answers.com/fun

The three sentences don't have the same meening.

#1 -- something enjoyable

#2 -- something to make you laugh

#3 -- something to keep your attention

Answer 2

Sorry -- meaning (not "meening"!!)