Dragcave is a browser adoptables game, wherein you just... click on dragon eggs to adopt them, then use their HTML code to display them somewhere and they hatch/grow as they receive views and clicks!
Link to the wiki, to learn more.
Well, even though I just called it a "game", it doesn't actually require you to actively do much. The fun of it is to just collect different dragons, and then display the pretty pixel art somewhere. There ARE some actions you can do, like breed the dragons, or use their abilities, but overall, it's just a fun collection game.
If you have a Neocities website, it can be fun to use the dragons to decorate your page. However, if your website doesn't get a lot of views, it can be hard to grow the dragons (they need hundreds of views to grow). Worry not! There are websites where you can post your eggs/dragons to, so they passively receive views/clicks. Here are three I use:
If you're interested, then head over to Dragcave to learn more and get your own dragon!