In my Computer Applications class this year, I have changed my bellwork from writing to completing small tasks. I've been very happy with the results. Each bellwork task serves as a small formative assessment for the day. The bellwork shows me they can remember what we just learned, or have mastered a prerequisite skill for the day's assignment.
Every single one gets checked daily. It takes around 8 minutes at the beginning of class, and it saves re-teaching time later in the lesson. I pick one skill from the assignment that is essential, or I predict may need re-teaching, and make sure students can do that first thing. Checking every bellwork every day means that no student, no matter what dire academic straights he or she is in, can get through the class period without showing that they know something.
Today we worked with Audacity. For bellwork, students opened a 30 second piece of music and changed the pitch 40%.
When we worked with Adobe Fireworks, I made single-tool tasks for the students like
Remove the tree from this picture with the rubber stamp tool.
Use the effects menu to change Bob Hope to match the background colors.
Cut the penguin out using the lasso tool and paste in 5 more so he has company.
When we worked with Flash, students would create simple tweens.
Starting class with these small tasks has, I believe, ensured that students are ready to learn. It has been valuable feedback for me as a teacher, and I get it right at the beginning of class.