I have been approached to do a cake decorating party (2hours) for a kid's birthday (10 kids). The idea is I would prebake little cakes, travel there (about 35 minutes drive), brings tips/icing/spatulas/etc. and show the kids how to decorate their own little cake (a 6"maybe?).
I'm thinking this could easily turn into:
3 hours of pre-event labor (shopping/baking/cleaning)
70 minutes travel round trip
2 hours for the actual event
1/2 hour clean-up after