Oh, that's a fun one!
I think projects that involved random numbers for colours or positioning elements can be super fun and easy for beginners. Animation is always a hit too. Getting something moving on screen with code is always a fun moment for folks that are new to programming. (And it's super fun to teach!)
If you haven't read it already, Learning Processing is my favourite intro to programming book. I love how it gets you making things, even if they're just small things, right from the early chapters.