Could you link us to something explaining the number & the throw? (BTW I saw your talk as a kid, though before I knew any real maths. Very fun!)
http://news.ycombinator.com/item?id=4947536
I don't imagine it will get any upvotes, but it's a place to put some of the more detailed discussion, if anyone wants it.
In short, we juggle to a fixed rhythm with the hands taking it in turns. For a given throw, the number is when that ball will next be thrown. Time between throws is made up of "Flight Time" and "Dwell Time".
Under reasonable, simplifying assumptions, the Dwell Time is always one beat, so the time of flight is always one less than the number describing the throw.
And thank you! Nice to know you remember it being fun.