A few months ago I began to make a simplified version of muesli. I can make it with four ingredients and alter it to add various fruits. It should be made ahead of time so that the mix has time to set, the oats need to absorb the liquids. It can be kept in the fridge for several days. To me, it is cool, smooth, thick, and I like it very much. Sometimes, I will go for a few weeks without making it, but usually there are the ingredients on-hand.
I use equal parts yogurt (plain/vanilla), oats, juice (i use apple), and fruit (i've used canned pears, dried berries, fresh peaches/nectarines). I mix it together, cover with plastic wrap, pop the bowl in the fridge overnight and POOF! that's it. Sometimes I slice a banana into it just before I eat. I make a batch with a cup of each of the 4 major ingredients (yogurt, oats, juice, and fruit); but if you haven't had it before, I'd recommend starting with a half cup each, that way you can try it and see what you think.