I am particular about my mashed potatoes. I like a mix of russets and Yukon Golds, but I rice the Yukons. (I don’t like the texture of riced russets.) This necessitates keeping the spuds separate during cooking, because they’re hard to tell apart once peeled and cooked. Rather than break out two different stock pots, I just divide my big pot into two portions with a small sheet pan.
The sheet pan — which I borrow from my toaster oven — keeps the potatoes from getting mixed up while allowing the salted water to boil around both. When they’re done, I just fish one type of potato out with a spider, then dump the other in a colander. I mash the russets, rice the Yukons, and then return everything to the pot to be mixed together.
Of course, you don’t have to use a sheet pan, any flat-ish piece of food safe metal will do, and you don’t have to stick to potatoes. You can use this trick to blanch vegetables with different cook times, a vegetable and pasta, or two type of pasta. Beth told me her children sometimes demand different pasta shapes; parenting sounds wild as heck.