My specialty!
I'm as active as the next camper, but come lawn chair time I am NOT getting up to play fetch with the dog.
Here's my guaranteed-to-keep-me-settin'-and-Millie-happy solution, though it works only with a dog who will chase soft toys etc. as eagerly as a ball.
I bought one of those retractable leashes and come "play time" I put a stake in the ground just about as far away from where I'm sitting as the leash allows Millie to go. I then hook a bungee cord to the stake and the leash to the bungee cord. (Purpose of the bungee is to absorb any "shock" if she outruns the length of the leash.) The beauty of the retractable leash is that it extends/rewinds according to what the dog is doing, and swivels on the stake. Those features mean that it virtually never becomes tangled up, stopping the game.
She now has almost thirty feet of distance to run for the toy, counting leash length on both sides of the stake.
I then sit comfortably in my chair and fling her "toy" a distance calculated to be within her reach. This part takes practice and as I said won't work with a ball that'll continue to roll....don't want to "clothesline" the dog or, heaven forbid, force me out of my chair to retrieve it myself.
She eagerly chases/fetches the toy, and the "rule" we've evolved by Mutual Consent is that I won't throw it again unless she brings it to me and puts it in my lap. She can toss it around/play with it as long as she likes and better yet, I don't have to so much as BEND OVER to pick it up when it's my "turn" to throw it again! :B
We've gotten so good at this game that Millie actually knows now exactly how far the leash will let her go, and on the rare occasions when I overshoot, she'll stop short before getting pulled up by the leash.
Side notes:
One does have to be careful to play this game only where one "controls" enough territory where the field can be kept clear of people that might wander in and get entangled.
" Not every mind that wanders is lost. " With apologies to J.R.R. Tolkien