I can confirm that both of these are great if you like either puzzles or rogue-likes, respectively. Simon Tatham’s Puzzles is easily my top played mobile game.

Of course. I’m just adding that there is some logic to fahrenheit in day to day use.

As you approach 0°F it is getting dangerously cold. As you approach 100°F it’s getting dangerously hot. Celsius is obviously better scientifically, but fahrenheit is pretty reasonable for everyday use (unlike other imperial measurements).

Calibre is the main program for doing most things with ebooks. It’s plug-in support allows for things like deDRM that you can use for stripping DRM. There are a lot of tutorials out there for it.