If you're looking for a fun and educational day trip for the kids, look no further than Mrs. Grossman's Sticker Factory in Petaluma, CA. It's just 40 miles north of San Francisco and about an hour and a half drive from Silicon Valley. They offer factory tours four days a week, Monday thru Thursday (Friday visitors get a "virtual" tour). Tours cost $3 per person above age 3, and include a video presentation, a guided factory walk, and lots and lots of free stickers.First up, visitors are ushered into a room where they are given a couple of stickers by the tour guide (I've heard some guides are more generous than others, but you'll end up with lots of stickers no matter which guide you get) and shown a short video hosted by Angus, Mrs. Grossman's granddog. The video gives an overview of how Mrs. Grossman got started, the production process and more. After the video, visitors follow their guide and walk along the factory floor. They get to see every step of the process, from design to printing to cutting and packaging. Children will be amazed at the huge rolls of stickers stored in floor-to-ceiling racks.At the end of the tour, visitors are led to a craft room, where each child is given a sticker craft activity. Ours was a decorate-it-yourself postcard; kids could put stickers on one side and scribble a message on the other (or get mom or dad to do it for them). Outside the room was a little cardboard mailbox where kids could drop the postcard if they wanted to send it to Angus the Dog. My kids opted to keep their postcard and send it to their grandparents in England, but many children were tickled pink at the thought of writing a postcard to Angus. And there were more than enough stickers left over for a separate craft. After driving all the way to Petaluma, most Silicon Valley families won't want to head right back home again when the factory tour ends. Not to worry; you'll spend enough time at the Mrs. Grossmans Company Store, where they offer stickers, sticker albums, and all kinds of supplies, many at a discount. The sticker grab bags are an especially great deal! And the Visitor Center has an indoor/outdoor dining area where visitors can purchase a snack from their vending machines, or bring their own food (they even provide paper plates, napkins, utensils and a microwave). Or you can stop by downtown Petaluma or San Francisco to round out your day.