I have a neighbor in his 80's who grows veggies and sells them on his front porch "when he feels like it." He has a little sign he puts out by the road, and the bowls of what's available are on his porch. You go up and knock, and he'll come out and chat your ear off if you let him. I love to go there. I also love the fact that he is having fun making a little pocket change.
My SIL does crafts year round and does a craft show twice a year -- just before Christmas, and just before Easter. She makes $900 to $1200 profit each time, and has a blast with her crafty girlfriends. My brother made her a portable wooden stand -- it's two A-frames with slots, and boards that fit in the slots for shelves -- so she doesn't need to rent the tables for a booth.
Another neighbor and her daughters have huge garage sales about four times a year. She told me that she makes around a thousand dollars on the weekend. She collects people's cast-offs all year long and sets up a really nice sale in her yard -- lots of tables, ropes tied from tree to tree for the hanging clothes, books on roll-out carts, etc. They also sell drinks.
Another man in this area buys used cars and resells them. He works on one car at a time, in his garage. His wife says it brings in a few hundred a month.
What are some more ideas for people to make "pocket money" when they are retired?