I suggest locking them in the cellar...

...to be serious though, I do babysitting. Some kids are annoying and constantly demanding attention whilst others are quite good and helpful.
With both types, one needs to always remain in control. You say something, they do it and they will be rewarded with extra Television time or something that they like. If they do not, then they are not rewarded. Simple.
Fun things to do is play board games.
Read books, if they are very young and are being difficult you get a favourite toy and speak through it for example:
''Monkey wants you to do tidy up now.''
It may feel stupid but it works.
Television may be good, but it depends.
Or you could take them out to the park or go out in the garden and play a few games.
Or you could do a ''treasure'' hunt around the garden.
Or build a ''tent'' inside the house. Those are fun, unless the parents have a problem with it then it's the kids idea.
You have a lot of options. Just play with them. Have fun with them but remain in control. Some kids, if they think that you are easy to be intimated will be the one's who control.
^
Hope some of this makes sense.
Gah, I hope I don't also sound like a tyrant.
