I found these 3 Ways to Wake Up Attendees of training courses simple yet interesting.
Online, you can't really drop a book next to the desk of a sleeping attendee. Instead, shake things up with one of these fun activities.
Where in the World?
Have attendees use the GoToMeeting highlighter to mark where they’re from on a map before the meeting begins. This will give them practice with the Drawing Tools as well as help them get to know other attendees.
Secret Word of the Day
At the start of your meeting, tell attendees to listen for a secret word or phrase during the course of your presentation. The first one to type "Secret Word" in the Chat pane (after you say it, of course) gets a prize. This will increase attentiveness - at least up until you say the word.
This takes a little preparation, but could be worth it if you give the same presentation a lot. Provide attendees with Bingo cards listing topics you'll be covering during the session. The first person to type "Bingo!" in the Chat pane wins a prize. Bonus: Attendees will be sure to remind you if you skip a topic.
GoToMeeting Autumn 2010 Newsletter