When I was the manager of two food kiosks in a mall, we had a LOT of young resentful high school workers who worked only for Summers or for holiday $$ or for prom, etc.. so their enthusiasm just wasn't there. This is what I did, and it not only worked, but several other food stations picked up on it. My teens really liked it. This may help with keeping it enjoyable ever changing and not turn mundane and then into "work".
I laminated different job titles on paper and put them into a container and everyone would pull a slip out. It was fun because they never knew what they would get and if they really didn't like it, they would switch w/ someone. That was fine, as all the jobs got done! ;) Some of the slips were: clean drains, clean filters, sweep/mop dining area, refill condiments, etc...
For your little helper, maybe laminate some that are actually harder than others and some that are just silly fun. Dust bookshelf and entertainment center, empty bathroom garbage, check mail, set table, make up bed, clean counter-tops, etc... Then, he can reach in and each slip is a big surprise! Maybe you can make some that are not exactly work, like "rub mommy's feet" or "start the bath for ____" or "pick flowers for the table vase" so that they don't all include labor, but connecting with others or beautifying his space w/ the concept of helping and cleaning. Also, they sell kid size tools like vacuums, brooms, mops, shovels, rakes, etc... perhaps implement those into the "chores"? OH, also, if there's not too much in his ability range to do on a day, maybe you can "accidentally" spill some dry cheerios or make some other little task appear to do so he doesn't get stagnant if there is a slow day??
Dunno if this sounds good, but hey... thought I'd suggest it.
Enjoy it while it lasts!! :)
L.