I know it is a little babyish but it will still make you some money. If you are to embarrassed to do it, and you have a little sibling(you can't trust your older one) they do it for you. Of course they might not do it for nothing so say you will give them a dollar and to them that might seem like a lot. You can really make some money doing this.
You are so right...preteens may think that having a lemonade stand is only something little kids do. But, if it's done right, it can make some real money. One big key is picking the right location. You will also need to get your get your supply list together and even consider a business plan (including paying your younger sibling) if you are really planning to make this your summer job. Thanks for the great suggestion!