SB says have an olive oil tasting party where you can compare oils from different regions. (Do they really taste that different?) Yes. One reason is the type of water and different growing conditions. And regional differences of when and what kind of olives they pick. (So you put these parties together how?) Put them in shot glasses so you can sip them straight. Have everybody take note of the characteristics they're tasting and the finish. It's good to have bread nearby to cleanse pallets. (Is there a guide line for when you'd use a certain olive oil?) it's always good to use an oil from the region of the kind of food you're cooking. (What are tapas?) They're Spanish traditions, they originated as bar snacks.