Best free online courses Websites

We already round up some of the best free online classes in our Lifehacker U series, but the classes we highlight come from a variety of sources around the web that offer tons more than we can feature. Let's build a list of the best sites, schools, and resources for those free classes you can take from the comfort of your desk.

When we do Lifehacker U, we highlight a series of individual classes that we think are worth looking into for that semester or term. That's great, but there are tons of great colleges, non-profits, and more that offer great classes year round from physics and mathematics to programming and web development, and everything in between. We'll get this list started, as usual, but let's hear some of your favorite resources too!

Share your best resources for free online classes in the discussions below, like this:

1. Include a picture, screenshot, whatever! Anything to add a little visual interest, especially if your suggestion is a website, a place, or something like that.
2. One suggestion per comment please! Let's keep it simple and easy to read—if you have multiples, and we hope you do, add them as separate comments! We really want each thread to be about one great website or resource that has tons of great classes to offer.
3. Try not to repeat suggestions! If you see someone who's already suggested your favorite resource, click the star and reply to their comment with your own story and thoughts. We still want to hear it, just make it part of the thread!
4. Tell us about it! Maybe it's a community that's open to everyone, maybe it's a college with free classes for everyone but credit classes for students—whatever your suggestion is, tell us all about it and why you love it!