I really like to see what fellow developpers out there built. From famous frameworks to small side projects, I always find it interesting and impressive what awesome stuff people are making.
Recently, I discovered the GitHub explore tab, that you may or not know (personally, I didn't even knew it existed). It's located at the end of the main navbar.
Here's what it looks like :
Basically, it'll provide a "news feed" with projects and issues you may be interested in, along with some apps that you could introduce in you workflow and GitHub news.
To build your feed, you'll need to select a few subjects from Topics tab, which is also probably the most useful section. There are a lot of categories available, from general computer sciences stuff, to specific programming languages or even frameworks.
The Collections tab is also pretty cool as it contains a curated list of projects related to a more generic subject.
You should definitely check it out this feature if you got some spare time !