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.
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)