I am cursed to have a short attention span. But I think it has made me a more interesting teacher/preacher/writer over the years. If I start to bore myself, I figure it's time to switch up what I'm saying in some way. I admire the way Seedbeds has set up the 7 minute seminary--just about the current attention span.
Consider what text messaging and smart phones are doing to us--and the purpose is not to pretend we can change it. If we can't deal with it, we're dead. If education can't lasso Facebook type things, it's dead. The "no lap tops in my class" approach is the sign of a loser teacher, someone time is going to run over like an avalanche. The "switch-task" mentality is here for the long haul, and if you can't deal with it, you're not.
This is why things have to begin with the attention grabber. The novel/movie starts best in the middle of the story, otherwise you've lost the audience a half hour before it gets good. The curriculum needs to start with what is perceived to be immediately relevant--you can go deep later. Give a problem that needs solved. Don't hold a session on how to do PowerPoint. Come alongside me while I'm designing a PowerPoint for my next class.
We learn by doing. We fall asleep in a lecture--and that goes for traditional preaching as well. Don't give me all the background in preparation for the juicy stuff and expect me to still be in the room when you get there.
Welcome to the new common sense.