Bill Kendrick sent in the following:
My friend Mark has begun building an adapter that lets me connectreal Atari 2600 paddles to a PC’s joystick port. (Instructions andschematics are part of the documentation to “Stella,” the Atari 2600 emulatorfor Windows/Linux.)
My game “Circus Linux!” is a clone of “Circus Atari,” which used paddles,so I’ve added support for this adapter in the latest release, 1.0.3.
Instructions for building an Atari paddle controller adapter can be foundhere.
Circus Linux! 1.0.3 Source: