I don't have a ton of suggestions but I bought a coloring book from Walmart
that's Jo-Jo's circus and has really fat crayons that comes with it. I put Nathan in his high chair with the tray on and give him one crayon at a time. I also put pretzels on his tray so he eats the pretzels and not the crayon (he did bite the tip of the yellow but didn't eat anymore as long as the pretzels were there). He loves to mark up the page and I don't mind if he marks up the tray a bit too.
Then after he's full of pretzels I give him one thing of play-doh. I give him the container, lid and the contents (usually blue). He puts it in the container, takes it out, puts it in, takes it out, puts the lid on, asks for my help getting the lid off. Every few minutes I pull the play-doh apart and show him that it molds or comes apart easily or squishes together. He'll play with that for a good 20 minutes to half an hour before starting to drop it on the floor for fun!
Since we can do both in the kitchen it lets me get dishes, counters, floors done etc. without putting him in front of the TV and he's starting to understand the physical properties of play-doh too which I think is pretty neat!
Well, that's all I can think of at the moment but let me know what you end up with that works for you since our kids are so close in age.