Most slow down, a bit like hibernating (see Yahoo answers to the same question: http://answers.yahoo.com/question/index?qid=20080202020452AA189mU). Trees that don't lose their leaves can continue to photosynthesise in winter. Some trees flower in winter and others grow berries, so these ones are obviously still active above ground. All of them are active below ground - their roots continue to grow. (See this article: http://www.commercialappeal.com/news/2008/nov/28/tree-roots-grow-during-winter/)
Why are video games so addictive?
Because it's so fun, it's like you barely started to play at 1:00 and you stop at 3:13 but it feels like you just played for 30 minutes. And it helps kids learn to use there hands a lot more.