Lemonade Stall
You're selling lemonade at horse shows (I had to make it horse-related some how!). You get to set the price and quality of the lemonade (how many lemons, sugar, ice). See how much money you can make in 30 days! Your customers will give you feedback, and tell you if it's good (MMM!) bad (Yuck!), etc. Increase your popularity to get more customers-- and watch the weather carefully, it controls demand for your lemonade!