We have been playing a game that has become quite popular.
It's called Set the Table.
Gather several objects (a block, pencil, pair of scissors, cup, toys, etc.)
and arrange them on the table or floor.
Ask the other people playing to "study" the set-up. Then ask them to close their eyes.
While their eyes are closed, change one thing about the set-up and then ask them to open their eyes and see what's been changed.
It's easy to play anywhere and a good way to practice noticing details.