The tricks were getting serial communications to occur between the aim and the C64 on the modem. But we needed to leave enough of the modem intact to allow it to sense a ring and pick up the phone. Then we had to impose the Voice synth output onto the phone line via a hand wound transformer (8 ohm to 300 ohm if I recall correctly)
I remembered I hand crafted the rom firmware in in a cartridge that we wire wrapped together to read the AIMs data and craft a weather report. You could call the thing from anywhere and get the weather up to the minute. BP, Rainfall, Wind Speed and direction, We even had cloud cover sensors with trends. It was pretty cool. Of course I farged the wire wrap job and forgot to reverse the pin connections initially. So I just bent all the firmware roms pins up 180 degrees and inserted the chip into the socket upside down and mirrored. Worked like a charm.
I can say that Database apps in .NET are a hell of alot easier now.
I'll bet Larry has seen some seriously kludged stuff like that as well...