A util is a cute little thing. Economists use it as a convenient word for a unit of satisfaction. Everything you consume has utils in it: books, cars, hamburgers, wood, insurance, even the air you're breathing (that has a LOT of utils!).
Utils are also related to opportunity cost (what you give up to have something else): the utils of what you give up apply to what you end up having. However, there is no standard for utils, like with money. A shirt may cost $17.99, but that cost is the same for everyone. Joe here puts that shirt at 79 utils (it's got his favorite band on both the front and back), while Allstair thinks it's worth maybe a little less than 4 utils, being that he's never heard of the band nor would he wear the shirt in public.
If you want to play with utils, the next time you're at a big family dinner, say out loud how many utils a particular dish you think will give you. For Aunt Jack's Rhubarb pie you'd say "40 utils" while when they pass you the liver stuffing you'll pass it on, saying "negative 40 utils". What fun!