Welcome Jonny!
By the word Develop, do you have to write a bot program or are you looking to enhance an existing bot by interfacing OpenCyc?
Check out the Hal main page if you haven't already.
Hal can learn facts, make inferences, look for and respond to patterns, show emotions, tell jokes, respond to insults, tell date and time, remember appointments, email addresses, search the internet for practically any topic and draw from a huge knowledge database (over 33 megs), accepts 3rd party plug-in enhancements and much more. Hal's personality begins to emerge over time spent chatting with it.
People are writing plug-in enhancements that will attempt to allow Hal to become even more interactive with regard to moods, behavior, emotions, events and even self correction.
Personally, that's a wheel that would be quite difficult to reinvent.
As for integrating Hal with Cyc, I'd have to see what Cyc is capable of first. IMHO, I think Hal has the vast majority of bot programs years behind.
Regards...