Ask HN: What are some of the best cloud resources you've come across?

Hello everyone,

I'm in the midst of pulling together a repository of the best cloud computing resources readily available on the internet. I'd appreciate your help and opinions on what you feel are some of the best cloud computing resources you've come across. These resources can be generic or vendor specific, it's all fair game.

Currently I've broken down these resources into buckets:

- Online classes - White papers - Books - Presentations - Essays, blogs and articles - Audio/podcasts - Sandbox/experimental environments - Other (anything not listed above)

I'd love to hear what everyone has used to get up and running on cloud computing (beginners), what you've used to advance your knowledge (intermediate), and what you've used to master your craft in cloud (advanced).

Any and all submissions will be taken into consideration. Obviously those resources that others vouch for will be prioritized but everything will get an eye.

Thanks!