This trick requires a TV with a Cooking, Fishing, or Gardening channel
and a video game system. Have a Sim sit down and watch television. Switch 
the TV over to one of the previously mentioned channels so that the Sim 
can start earning his or her skill point. Then, have a second Sim go over
and start playing video games. Notice that although the TV is displaying 
video games, the first Sim still has the skill meter above their head. 
Allow this Sim to sit there for as long as they please until they decide
to do another activity of their own. After that, the skill meter should 
stay above their head until you start another Cooking, Fishing, or 
Gardening skill activity. As an added bonus, you can train two skill 
points at once. For example, work out and both the Athletic and Cooking
skills will continue to rise. If you keep repeating the steps until each
skill channel has been viewed, the Sim will keep learning the three 
skills as he or she goes on about their daily life, and four when doing
skill activities.