Forgive this stupid question, please. How does a person challenge someone who is not on the Live Waiting List?? I've noticed that I have been logged on, but not on the Waiting List, just waiting for my friend to come up on the Waiting List so I can challenge him, and I get incoming challenge after incoming challenge. Again: how is it that someone can challenge someone else not on the Waiting List?

To challenge another member to a live game, just go to the "Live games" drop-down menu and choose "Challenge." In addition to all the other challenge options, you will see a list of challenge-able members. These are basically all logged in members, who are not currently in a game (and not set up for simultaneous games), and who have their live game challenge option turned on.
 
If you click directly on the "Live Games" tab, you will see a list of all the Live Games features as well as links to video tutorials. Feel free to check out the Live Game Challenge video tutorial.