With Asterisk and some voip client (even some modern phones) and some ZMachine modules you could play from Zork to tons of adventure games for the ZMachine at I

With Asterisk and some voip client (even some modern phones) and some ZMachine modules you could play from Zork to tons of adventure games for the ZMachine at IFDB, from Anchorhead to Tristam Island. Which is kinda the reverse of this, reusing phones to play a text adventure.