A SIP service that offers a decimal to hex/bin conversion service.
You are in the supermarket, and suddenly you feel the urge to convert the price of that loaf of bread to hexadecimal. But how are you going to do that with just your dumbphone?
Easy!
Earlier that day, you created a sip.conf configuration file, ran this python script on your dusty old server, and connected it to your favorite landline SIP service. Lo and behold, hexadecimal and binary is now within arm's reach from anywhere on the planet (mileage may vary)! It's the best thing since sliced bread!
Released in CC0 (Public Domain) for everyone to tinker at.