Your Chromecast can now be a source of dry wit and occasionally entertaining TV shows with the newly added Chromecast support for NPR One and Watch ABC. The NPR app should work on just about every device under the sun, but the ABC app is oddly picky.
The NPR app offers access to programs like Morning Edition and Radiolab with a curated feed of content you control. There is also a feed of content from various local NPR stations—it's actually better than most of the dedicated local NPR affiliate apps I've seen. The Watch ABC app has live streaming in a few markets, otherwise it's all on-demand content. Be aware you need a valid cable subscription to watch full episodes.
Both apps are showing as updated in the Play Store, but the NPR One app is doing a staged rollout (still installing the old version). I'm not seeing the Chromecast functionality in the ABC app yet either. You might not even be able to install the Watch ABC app, depending on your device. It lacks support for some popular devices like the Nexus 5 and Nexus 7.