There are several things I've learned about teenagers in my teaching career, and two of them tend to go together. (More on the others later). My mantra, especially with difficult classes has become, "If you can make something into a choice, it will be a better day for everyone." This can relate to discipline as well as actual assignments.
alternative high school, if I wanted a student to do something, I'd give them two options, even if I knew they didn't want to do either of them. Usually, that was enough to move them at least closer to the objective of the lesson, even if it still wasn't perfect. Today, when I have students that are (I'll just make up a quick, implausible example here), on Facebook or Youtube when they should be working, I tell them to close it. If they don't, the next step is "You close it, or I close it." (To most kids, keyboard shortcuts are still a total mystery. I tell them it's magic :-)) Generally, they'll start moving to close. All kids want is to feel like they're not on a one-way street.
In terms of curriculum, whenever I'm designing assignments for regular classes or my technology classes, I do everything in my power to incorporate choice into the project. When I can do this, everybody is happier, me included. For instance, my 8th graders are currently working on a project about the Vietnam War on Glogster. I gave them a list of things to include, and they chose 3-4 in each category. Added bonus: they get a big long list and are overwhelmed, and then I tell them they don't have to do it all :-) My 7th graders are making interview videos in iMovie about technology and how it impacts us. While they didn't have a choice on the general topic, they can choose the specific question they are asking people, and then can choose what the final product looks like.
Choice and motivation are like spring fever and state standardized testing: you don't get one without the other. The 7th grade project has made my life a breeze this week. The students know how to do all of the pieces, from last week's instruction and previous assignments, and I just let them go. I've literally spent all year trying to keep them off of great programs like Photo Booth because they weren't in my assignment. I finally figured out that I just had to design an assignment using photo and video and they're all over it. Just the specific technology is motivation enough. Last year, I had students supremely motivated to learn about tides, not because of the topic, but because (without any previous instruction on tides) I had them find a video describing how tides work. (Added bonus to this assignment: Youtube was blocked, so they had to find a way to work around it.) Again, sometimes just the technology itself is motivating. Imagine if you told students to take 5 pictures with their cell phones and write a story to go along with them. Motivation? Check.
[Note: all the links in this post are how these tools relate to education.]