Set a timer for a certain length of time.  Work on something until the timer runs out.  If you still feel the momentum, reset the timer.  This can apply to tasks that you need to do personally, but also to things that you might do as a family.  Set the timer on a Saturday morning for 1 hour and work together to accomplish a list of quick tasks.  Everybody works together, and then everybody is free to enjoy the rest of their day!