To add plugin shortcode to some text area of a widget that you’ve built, follow these three steps. Keep your eye on the my_content tag.

1. Make sure that the variable that you want to add the short code to has apply_filters applied to it.
   $content = apply_filters('my_content', $instance['content']);
2. Throw the following two lines into your functions.php file.
   add_filter( 'my_content', 'shortcode_unautop');
add_filter('my_content', 'do_shortcode');
3. Add the shortcode to your widget.

Steps two and three come from http://digwp.com/2010/03/shortcodes-in-widgets/.
Step one was sort of inferred from http://codex.wordpress.org/Function_Reference/do_shortcode

You told me that good things come to those who wait. I waited for you Janet, but you were bad.

Sometimes you don’t have to do it well, you just have to do it.

Vowing not to leave his apartment until he had completed his novel, James was found sitting at his desk — dead, pen in hand, paper blank.

The idea behind Driver Ability Days was that with people failing their drivers tests magnificently and getting behind the wheel anyway, we might as well sanction the behaviour and try to control it somehow. At first, we thought that we would let everyone that failed their driving test drive only on certain roads and leave the rest to those who actually knew what they were doing. We soon found, however that the failers went wherever they wanted and remained a danger to licensed drivers (not to mention the public at large). The second iteration of the program entailed changing the driving test altogether and eliminating any sort of pass/fail dichotomy. Everyone would have a numerical score and based on that score, you could drive on certain days of the week. This way, those drivers with scores ranging from 80 to 100 did all of their driving on Mondays for instance and those with scores of 30 or less drove on Fridays. It turns out that if you let the drivers with the highest scores all drive together, there are a greater number of vehicular homicides and car accidents; each driver thinks that he’s the best and puts the onus on the driver in the next car to watch out for danger. The curious thing is that the drivers with the lowest scores were either too scared to drive (thinking that another bad driver would crash into them before they made it out of the driveway), or exercised such vigilance that the accident rate stayed pretty consistently near to zero. After a while, the city just started giving ambulance drivers and traffic cops Fridays off. Some gas stations closed down too since there were so few cars on the road. How did drivers in the other ability groups get around on days that they weren’t allowed to drive? Well, some biked, others took public transportation, some just stayed at home. Sociologists discovered that implementing Driver Ability Days led to stronger family bonds since parents were forced to stay at home with their kids. The flip side of that discovery was that the number of child murders per year got a slight bump. It’s unfortunate to be sure, but the city saved a few million dollars on maintaining kiddy parks. The ones that took the subway to work so consistently debilitated the network that MetroTrans, the private corporation that ran it, was found to be incompetent and the city took possession of all of the buses, trains, ferries, and light rails by eminent domain. Some citizens said that it was a money grab but dissent dissipated pretty quickly once the fares decreased to about a quarter of what MetroTrans was charging.