These all sound like fantastic ideas; I enjoyed reading this thread.
Here is my current out-of-left-field idea for injecting some enthusiasm for writing into my ds' life: I have signed him up for a once-a-week cartooning class; supposedly they will be working on character development, which I hope means some writing of words... if not, it should still be fun for him, he is really really excited about it. It starts in a week or so and goes for a couple of months.

https://twitter.com/asimom, https://contributingfactor.wordpress.com