What is the etiquette way to go about this in a conversation?

A skilled conversationalist knows how to "bend" boring conversations back into more normal channels.

"How did you get started collecting Kachina dolls?" you could ask. That might lead to talking about trips out west, then travel in general, then places you both had been, etc.

The first thing you need to do is learn that etiquette is based on consideration for others. Apparently you don't have any.

just ask thenn to explain it

In order to be polite you're supposed to feign interest...this is why it's called 'small talk'. No one really enjoys it but it's a social necessity in some cases.

You can either stay on topic or change the subject to something more to your liking.

Well for pete's sake, a mannerly person CHOOSES to take some interest in the conversation, even when the topic is something unfamiliar. Instead of tuning out when you're not being entertained, try LISTENING -- then that topic will no longer be "something you know absolutely nothing about." Maybe they don't teach this in school anymore, but you can CHOOSE to focus your interest by an act of will instead of taking an interest only in those few things you find particularly amusing or entertaining.

And as another Respondent notes, it's not rocket surgery to ask questions like "How did you first become interested in stamp collecting?" or even "Can you say that again without all the technical jargon?"

If you are too selfish and self absorbed to listen to others, and only want to talk about you and your life you don’t deserve friendships.

If you don’t want to find out about others lives you are truly selfish and I feel sorry for you.

We can all learn from others.

Or don’t you want to?

Clearly all you want to do is talk about you.

Just say you have to go, sorry, but was good talking to you.