This month's challenge theme is Retro Electronics. Just create a model of retro electronics, upload it to Sketchfab, and tag it #RetroElectronicsChallenge.
Sketchfab writes:
This month we're throwing a community modeling challenge and the topic is one that was suggested by Sketchfab user neuroup back in September: Retro Electronics. Just create a model of retro electronics (real or imagined) using your preferred modeling tools and workflow, upload it to Sketchfab, and tag it #RetroElectronicsChallenge. At the end of the challenge, you and the rest of the community will be invited to judge the entries and choose a winner.