yes, Krakow
oh, that's awesome!
ok, here's a few pretty good travel-related ideas - and you don't need a lot of money to start:
some time ago we happened to be in Philly, and we went on a very interesting walking tour that was historical, but not the stuffy official boring lecture - it was a kinda quirky, some little-known amusing stuff about Ben Franklin, some very funny anecdotes about Betsy Ross, it was an hour, a whole bunch of people showed up and everyone paid like $25 or so. very entertaining.
there's a bunch of those tours in each big city here, which you probably know, some are themed (like "ghost" tours, etc.)
some other time we went on a bus tour (actually, it was more like a van, with TV screens for everyone) through the places where they filmed well-known movies in Philly - the guide would talk about the movies, make it funny and entertaining, they'd show clips from Rocky, Treasure Hunt, Philadelphia, all bunch of movies, hour and a half, about 20 people, I can't remember how much it was but much more than would cover the gas, the driver's wage, the vehicle, etc.
then we went to Scottsdale, a few weeks ago, they had a food tour - the woman would take a bunch of people, I think it was 20 or so, on a walking tour through a number of restaurants in the Old Town, we would sample some food and wine (and I mean, sample, a few bites in each place), she made money, we had fun, the restaurants would showcase their food so people would come back for a real meal. I forgot how much we paid, but the woman was saying she was running the business pretty much by herself, making a few tours every week, pretty much paid a full-time wage for a few hours of work a week.
tourists are a good source of money, Krakow is a great city, people would pay a local to show them around, point them to the right restaurants, etc. Or, they can do more of a concierge-type of business - make restaurant reservations, scope organized tours, help foreigners with getting train tickets, or whatever a person not from Poland would find difficult when visiting. minimal initial investment, decent profit if you know how to get the word out and make the experience entertaining.