Well, it's been a while since I did any real cooking, or even adapted any recipes so I'll post something closer to what I have been doing: Playdough! Home made playdough is really easy to make, it's cheap, but it doesn't last quite as long as the stuff you buy from shops. Make some for your next kids party and consider it disposable.
2 cups of plain flour (don't use self-raising - I did it once by accident and it makes weirdly fluffy, gloopy playdough)
1 cup salt
4 tablespoons of cream of tartar (no idea what this does to the playdough, but it's available in supermarkets)
2 tablespoons cooking oil
~ 2 cups of water
Traditional recipes say to mix all the ingredients over medium heat, stirring, for 3-5 minutes but I now tend to add boiling water to the other ingredients and nuke them for half a minute before stirring like crazy for about a minute. Either way seems to work fine.