Our older two, ages 11 and 9, have been learning fiddle, and are getting pretty good at it. When the weather's nice we'll occasionally go play somewhere public for tips ("busking"). It's better than practicing, builds performance skills, and the money is a good motivation!
We'll usually walk over to Davis Sq, tune the fiddles, set out the case, and play. We'll do a series of fiddle tunes from Lily's list, playing for 20-30min. Today I remember playing Sandy Boys, Angeline the Baker, Marie's Wedding, Cluck Old Hen, Coleman's March, Oh Susanna, Kittycat Jig, Hundred Pipers, and Trip to Moscow.
Since this is a performance we play one tune after another, with only short breaks to decide what to do next. If one of the kids doesn't remember how it goes or gets lost in the form, it's on them to figure it out and get back on, which is a skill I'm very glad for them to be learning. I'll play fiddle with them, switching between melody and rhythm to support where it's needed while still letting them show what they can do.
People often stop and watch for a bit, sometimes dance a little. Some people put in a little money, most don't, which is all fine. Today the kids made $28 in 25min, split evenly since they both played the whole time; given the diminishing marginal utility of money and my wanting them to be incentivized to play, I don't take a share.
One thing I didn't anticipate, however, has been the effect on household economy: they have much more buying power than either of us did at their age, or than they did even a couple years ago. Sometimes this means spending their money in ways that are thoughtful and seem well worth it (when our oldest wanted to save up $80 to get her ears pierced we went out busking a lot) while other times they're more free with their money than I think is prudent (a drink from a vending machine because they didn't want to use a water fountain). It's their money, though, and I think it's good for them to get a sense of how to spend it. Still, I'm thinking some about how to build more of a sense of fiscal responsibility.