Ask HN: What do you do with CI servers on off-hours?

We have some servers running all day for CI, but sit completely idle during weekends and nights. What are some good ways to make use of them?

CI infrastructure should be cattle not pets and there's nothing magic in a CI box that shouldn't be checked in like everything else. Put them into whatever local cloud solution you're using and start CI like you would any other ephemeral process. If they're in the cloud then shut them down or destory them when they're not in use. If you've already paid for reserved instances them put them into Kubernetes or whatever other cloud management platform you have running.