From @altosadventure on Twitter:

We’ve decided to make Alto’s Adventure and Alto’s Odyssey available for free for the next week to help anyone who may be practicing social distancing or self-isolation. We hope Alto and the gang can bring a little calm into your homes during these difficult times.

https://twitter.com/altosadventure/status/124000208371095961...

Link for Alto's Odyssey

These are brilliant games that I paid for and have spent plenty of time playing. Great to take your mind off things.

MacOS versions are free too (thanks mortyestmorty and brightaussie)

Alto's Adventure

Alto's Odyssey