Light gardening, sewing seeds, potting up, pruning, deadheading, tidying up in general. Pottering.
Reading a really good book, with a cup of tea and a shortbread biscuit/chocolate.
Playing music on YouTube, all the old pop hits and bits of classical music. Often brings tears but that's ok...
Walking anywhere green, leafy, away from traffic or on the beach.
Watching a good programme on the TV, often with nibbles.
Generally being totally engrossed with the activity, getting lost in it. And remembering good times.