Teens/tweens
This game is a scavenger hunt, but you hunt at the mall instead of at home. You will need to go to the mall ahead of time to pick out stores and clues. Some boutiques will let you leave a ‘clue’ envelope for each team that they can go by and pick up the next day. (Especially easy when it is a store where they have to buy something while there.) Pick out items that will be on your list: What is price of 50 ml Baby Phat perfume at Sears? What is number 3 single on the song chart at the local music store? How much is the blue leather jacket in the display window at the leather store? How much would it cost to buy 100 ml of candy from the color powder dispensers at the candy store? (Each guest would fill up a candy tube and keep the receipt as proof).
This game works especially well for birthday parties. You can tell each guest to bring $20 - $15 will be to spend on the birthday girl & the other $5 to buy stuff at the mall for the game – which the party goer gets to enjoy (like the candy tube). If it is not a birthday, or the guests don’t have any money, just look for answers to clues that they have to write down, pamphlets they can take for free, store flyers or coupons, etc. that they can gather. Once you know what items you are going to put on your list, you can make up clues for each item. For instance, if teams are 4 members each, you would have $60 to spend on the birthday girl, so part of their tasks might be to get a $20 gift card from one of her favourite stores. 
The clue could be "A&F has things she does lack, get a $20 GC before you come back” Vary the order of the clues for each team so they don’t follow each other around – and teams must follow their clues in order.
Each player must know all the rules before the game starts – you can even print them out. The adult/parent running the party can stand in the center area of the mall, or the food court, as a home base, to be available for questions or issues.
Team members must always stay together – if anyone goes missing, everyone on the team should report to the parent home base. Players cannot run in the mall, scream or shove or be rude to patrons, and will have a time limit. Teams could wear the same color scarves, headbands, etc., so any clue envelopes left with store clerks can be identified by color or team number. It is best if each team has 1 cell phone with the adult’s cell phone number for emergencies
Each team should have the same amount of cash, a bag to put items in and a sheet & pen to record answers on. Once the game is over, players can go back to the party goer’s house, or a coffee shop, etc. to go over the items and declare a winning team.