[asterisk-users] Equivalent of channel switching?

[Barzilai]

I still haven't figured out what is the "best practices" or Asterisk-way 
to do traditional switching between channels in Asterisk. I come from 
traditional computer telephony where there are buses such as MVIP, with 
streams and timeslots.
Asterisk, being born as a PBX solves most of the problems by "dialing a 
new extension".

I'll present a ridiculous and hypothetical situation:

User A has already dialed into Asterisk and is listening to some music 
through the phone.
User B has already dialed into Asterisk and is listening to some weather 
forecast IVR.
Event X happens (the Moon has aligned with Saturn) so we want A and B to 
start talking to each other.

This doesn't involve DIALING a NEW extension, I guess... both of them 
are already inside the system.

I can think of some convoluted way to do it; how do I do it the Asterisk 
way?

BarZ