Building upon your child's interests

I read a great CNN article on how some parents overemphasize "giftedness" at the expense of just helping our kids develop. 

The money quote: "Just don't think you have to drive yourself (or your kid) crazy signing him up for teams and classes to find activities he loves. Simply exposing him to different experiences will spark things that "click." Build on his interests"

Which leads to me the question - in what ways have you builded upon your child's interest?  Looking for some practical ideas. my 2-year-old loves sports and animals.