A few years ago I built a hub for a number of temperature sensors, based on the DS1820. Although computers with serial RS232 interfaces become extinct, most server machines still have these connectors, as they are useful for remote console management. The combination of a few DS1820s and the serial interface offers a very nice, cheap way to connect multiple temperature sensors to a monitor.
A few years ago I built a small rackmount unit for the IT Services department of my (then) employer, and published how I did it plus the associated software to link it up to the Nagios monitoring software. I keep getting mails from people who used the publication to build their own system, or to improve it.