Home Depot runs free workshops the first Saturday of every month for kids. We highly recommend them.
They are really mellow, and they have a little table in the back (by the bathrooms, how convenient) with an employee who has kits, paint, hammers, aprons, and glue for the kids.
The kids sit at the makeshift table (or on the tarp next to it if it's busy) and hammer and glue, then paint and put stickers on. And the kits are fun, like a sailboat or race car.
They weren't too out of reach for Little Brother, and were fun for Big Brother also (ages 2.5 and 5.5).
Can you guess who made which car?
p.s. They ask that you register in advance so they know how many kits to bring (here).