If you only read the same few sites with a similar slant, you can find yourself in a political echo chamber. To combat this, The Daily Mixer shows you stories from a variety of news outlets, but won't show you where they came from until you read them. The site takes the RSS feeds of 13 different news outlets across the political spectrum and puts them on a single feed with no labels for where the stories came from. You can scroll through, click a story and read the article in its entirety. Once you get to the end, you can click the source link to go to the original site to see where it came from.
In practise, the site is little more than a stripped down RSS reader (which also makes it nice if you want to read without seeing a ton of ads), but it's a handy experiment to play with your own biases. While you can occasionally see where a story came from (for example, FiveThirtyEight tends to include photos with their name on them a lot), The Daily Mixer will still show you some articles that you might not otherwise see if you dismissed a news site based purely on its name. The list of sites is also curated (there are 13 sources so far, but the developer plans to add more over time), so you don't end up with automated garbage.