Sites to learn programming online in an interactive way

I'm wondering whether there are programmers out there who have had good experiences with sites that offer programming courses in an interactive way?

Here are some of the ones I've heard are pretty good. Have you had any experiences with them, and do you know of others that can be added to the list?

Code Academy (for free)
Rails for Zombies (beginner level is free)
Try Ruby (for free)
TryjQuery (try out is free)
Code School (beginner level is free)
Team Tree House (subscription)