Each class period begins with prayer. I think most of my colleagues go pretty basic -- intentions, thanks, Father, Son, Holy Spirit, the essentials. My language arts block is twice as long as any other class (instead of switching, they stay in my class two periods, everyday), and I like to take advantage of the time to be just slightly more adventurous with prayer.
One of my experiments has been assigning a student to lead prayer once or twice a week. A few have gone "free style", some have read scripture, and one had us recite the Apostle's Creed. Most have gone the YouTube route. If they use a video, they introduce it and explain why they feel it's good for prayer, and those few sentences -- even though it's like pulling molars to get them out -- reveal an impressive understanding of the faith for 7th and 8th graders.
Some of the videos they've used so far this year:
What About Now? - Daughtry ("Embedding disabled by request")
The Lifehouse "Everything" Skit
Granted, they're not winning any prizes for "videos no one's seen yet", but hey, it's middle school. We're working up to originality.