Viva Pinata

I never played the original.  I have heard of it but thought it was just a kids game and never tried it.  Now the new one is out and everybody is talking about how great it is.  I am interested in it but really don't get it.  What exactly do you do in this game?  I know you have a garden and you try to raise these things but there has to be more to it than that.  Those that have it, fill me in.  Why should I buy this game?  I want to but I don't know enough about the gameplay to understand what the attraction is.  I am not knocking it.  I am genuinely interested in knowing.  Thanks.