The plan went like this. Everyday you had to pick a set amount of jobs with bigger jobs being more "weighted" and easier jobs being less "weighted". This could be done a couple of ways. You could have the kids pick, say, 3 jobs out of the "easy" pile and 1 out of the "harder" pile everyday. Or you could give the jobs a number of "points" and each child has to choose the same number of points, in whatever way they choose. So if they wish, they could end up doing 2 hard jobs or, say, 6 small jobs.
The key to this plan is it was first come first serve! There was definitely motivation there to get up and moving at a reasonable hour to get first dibs at the jobs. If you were the last one up, you get the least amount of jobs to choose from, or perhaps you have to take whatever is left!
Just another idea to keep the summer chores and activities interesting!