A few things we've done are Exploding Dots Machines [0] and stories about functions and boolean logic. [1] Peter Rowlett tweeted about a little sorting algorithm activity he did with his 6yo, which I've been meaning to try. [2]
Another idea I want to do sometime is a "Robot Mommy" game where the kids give me instructions and I interpret them super-literally (kind of like those "how to make a PBJ" games). I can see this one going in a lot of different directions, but I'm thinking to start by being a human Logo turtle and let them control my steps and turns.
I'm always on the look-out for more of this kind of thing, if anyone has any suggestions or recommendation!
[0] https://bancosparenting.wordpress.com/2021/07/14/exploding-d... [1] https://bancosparenting.wordpress.com/2021/05/08/pickle-and-... [2] https://twitter.com/peterrowlett/status/1479857933202739209
Another option is if you play games at all, introduce your kids to mods. At that age, I played video games with my dad/watched him and doing things like silly graphics mod replacements (turn Mario's sprite into the poop emoji!) help instill the concept that tech is built out of systems and components that you can change to get the results you want. It's just that since they're 3 and 5, what they want is likely to be quite silly.