Wouldn’t this be a funny concept? You put 2 robots who can recognize speech and talk back. One starts the convo, listens for a reply, and replies back. The process repeats.
Imagine how off topic they would go haha 
This would work, actually, but the conversation would only last as long as there are programmed responses available. I suppose if there’s a rather large database, there could be a two way conversation but it would still be a challenge without some sort of basic A.I. or there would be a pattern that would be repeated over and over. I guess you could use a randomize command that would randomly select phrases to mix things up a bit.
Two wireless robots connected to a PC (same or different one) might accomplish this using the greater power of the PC(s). 
8-Dale
Heh, you need to get the source code for something like Eliza (conversational AI program back in the 80s), add something like a current events feed to its way of generating of responses, and then find a way to prioritize or rank each event in the list so it can choose to reply to an input with either something related to that input or some other material from the current events items. of course you might have to detect situations where each participant keeps downgrading the others reply in favor of its higher priority thing it wants to talk about… sort of like watching to ‘me’ focused people trying to carry on a conversation with each other. 
One word: [size=150]Furbies.[/size]
yep, sort of. another product doing this sort of thing was the bugs bunny, daffy duck, and a couple other toys in the aisle at a local walmart a couple years ago… I made the mistake of pushing the toe of one to have it talk… it of course proceded to key the others and upon realizing what I had done I left the area pretty quickly (before my wife saw and I got razzed for it like the I do the elm… oh, nevermind. )
Ha ha… I would have done the same thing! 
EddieB, why do you say to carry on a conversation with each other? 