What do you do to motivate your teenager to do chores?

I have a chore chart. For instance my daughter isn't aloud to make any plans for Friday night if her bedroom isn't clean by Thursday night,and has not done washed the dishes on a Monday night straight after the family has finished eating.my daughter isn't aloud to do any thing until the dishes are done.I also have a list of house chores that she is welcome do to for a set price so that she can earn some extra money for a concert,phone credit or i pod credit.It's some times hard not to give into your child if they haven't done their chores and they want to go out with their friends,but after 2 or 3 times saying no and reminding them of the chore chart on how their are house rules with the chart that they end up doing all the chores and more.I hope that what ever path you decide to take that you find the right one.Take care.