Where to tap a vacuum line to?

I want to use the vacuum gauge I took out of my car. I haven't been able to find an easy or any place for that matter to hook up the vacuum line to on the engine.

My other car has a nipple thing with a rubber cap over it and the line hooks up easy. I thought those nipple things were a common thing on newer vehicles but can't find one anywhere.

 

you can probably get a "t" fitting and use some extra line and go off the vacuum line coming off the airbox...small line, but it may work.

 

I thought about that and could do it but don't think taking the vacuum reading from the intake is as accurate as from the plenum (or whatever they call it on a Tacoma). Maybe I'll go ahead and try it and see what kind of reading I get.

 

Brake booster?