Idle server uses?

You could get involved with some distributed computing project, like Compute Against Cancer.

Just please don't use your linode instances for this. Your use for distributed computing can stop other people from bursting and using otherwise unusued capacity. It's not friendly to other linode users…

No worries, not planning on doing that. I'm thinking more along the lines of providing storage/resources to an organization/project in need or perhaps a game server, etc. Any suggestions?

If you have several servers that don't do anything for months, why not consolidate their functions in one or two machines, get rid of the rest, and save $$ ? If you need the capacity later, it's trivial to fire up additional linodes or EC2 instances.

If, on the other hand, you decide to provide resources to a local charity or open source project (for example by hosting their content), keep in mind that you're making a long-term commitment there. You can't just quit when you yourself need the resources. Same goes for game servers. People don't like it when their game server disappears overnight. So, go ahead only if you're confident that you'll be able to provide the resources reliably in the long term.

@hybinet:

If you have several servers that don't do anything for months, why not consolidate their functions in one or two machines, get rid of the rest, and save $ ? If you need the capacity later, it's trivial to fire up additional linodes or EC2 instances.

If, on the other hand, you decide to provide resources to a local charity or open source project (for example by hosting their content), keep in mind that you're making a long-term commitment there. You can't just quit when you yourself need the resources. Same goes for game servers. People don't like it when their game server disappears overnight. So, go ahead only if you're confident that you'll be able to provide the resources reliably in the long term.

I would love to combine the servers but they are all(mostly) dedicated hardware that I colo. I can't simply decommission them. I understand I need to make long-term commitments to hosting charity sites or game servers. I understand all that but thank you for your contribution.

More specifically, I'm looking for someone to suggest charities looking for free space or popular games/clans in need of some hardware.

I had this "dilemma" if you will myself when I had all the hardware I had.

If VoIP is your kind of thing or you'd like to get a community going, TeamSpeak 3 is finally out, maybe that'd suit your fancy. You could use their non-profit licensing which is pretty non-restrictive.