Too cold outside? Some indoor activities

Because I live in a place where winter is sometimes horrendously unbearable, I tend to favour indoor activities when it's cold outside. It used to be that I spent winters at the movie theatre or in front of the TV, but now that I'm more into being active, I'm looking for indoor activities that get me moving but are fun too.

• Rollerskating or ice skating at an indoor rink is a fun and warm way to spend the day
• Curling is a great event for the family. Or, if you don't like the ice, how about bowling?
  
• eDiets recommends dancing around your house to your favourite tunes.
• A yoga class is a great way to de-stress during the holidays.
  
• If all else fails, take a long walk by going back and forth through the mall. Who knows -- maybe you'll get some Christmas shopping down while you're at it!

How do you stay fit when it's too cold to go outside?