ScratchJr is Scratch for younger kids. You don’t even need to write or read to use it but still it will show you basics of algorithms and enables to create simple scenes and games.
All you need is a tablet with Android or iPad and your free to go (app is free for both systems). It was, as Scratch, created in one of the best Universities in the World, MIT (Massachusetts Institute of Technology).
Similarily to Scratch, children can draw their ‘ghosts’ and background pictures and make them move (jumping dancing etc.). Simple loops and conditional actions are also possible. What children really like is the possibility to record own voices.
If you don’t have a tablet, you can also try some emulators for computers, e.g., http://www.scratchguide.com/how-to-run-scratchjr-on-windows-and-mac/ .
More information you can find here: https://www.scratchjr.org/
There are also a lots of ideas on youtube: