Yep. My girls are making use of their craft skills to provide baby layettes (knitted booties, crocheted afghans, hats, etc.) for a local charity (Tiny Stitches). I just keep a resource called “Tiny Stitches” on the schedule all the time so we can check it off whenever they work on it.
I also have one daughter who is learning violin, so I put a “Violin” resource on her schedule, M-F, and she just checks it off as Worked On each day she practices on it.
I suppose another possible way of adding something not originally scheduled would be to just put a note in the Daily Journal; but for something that will be repeated, I like having it on the schedule.