EDIT: This challenge can be really exhausting and it will be better to arrange a less demanding challenge with less than decade duration, maybe. So read this as a raw idea for inspiration. After all, we have a full month to think of different ways to take part in such a long jam and I would be glad to hear about your ideas. Have a nice time!
First of all, I agree that this jam is brilliant. 10 years of making games in a community of random people who are strange enough to join this fun, too.
Well, to increase the degree of fun I offer a decade long #onegameamonth challenge! The name is self-explanatory: make a game every month. From a super-duper-tiny press-F-to-win game to a mega next-gen photorealistic innovative title (who knows how far will you go). Make a game in an hour of do it every weekend — whatever you are comfortable with. Why is it cool? Because at the end of the decade you will have 120 (!!) games of different shape and size. Plus, you will improve your gamedesign skills. Moreover, it is a decade-long game-dev challenge. What can be more awesome?
Finally, this is completely voluntary (obvoiusly, but I should mention it). Join in whenever you want and leave whenever you feel like to. But we all know that you won't get this satisfaction if you don't have 120 games published ;)