As an in-class project, obviously you’d need to take the 3-hour (or 6-hour, if your class is long) option on the marathon cartooning project, but even so, it is well worth taking the class time to do it. Every time we teach the 3-hour comic, there are two or three students who have real breakthroughs as far as discovering new stories and drawing styles, and even in finding the confidence to attack a crazy project. Alternately, you can plan a special 24-hour comics day on a Saturday or other non-class day, or have your class participate in national 24-hour comics day.
Look at http://www.24hourcomics.com/blog/ to find the date in the current year, usually in October. Often, local comics stores will be interested in sponsoring or co-sponsoring the event. Maybe you can get a pretzel store to donate snacks! 24-hour comics are intense bonding experiences, and can help your class gain new heights in crits and general solidarity. The experience can also help students come together to continue helping one another to make comics after the class ends, as well.
We suggest here that students make minicomics. We feel very strongly that this is a vital part of learning to make comics, and suggest to you that you incorporate the various steps of making minis into the last few sessions of your class. We usually take three classes to teach minis while students are simultaneously finishing their final comics projects. The first class is an intro to the topic, and the assignment is to decide on format and content, order, and the design (through page 254). The next class is making a mock-up, and then the third class is making a pasteup. We ask students to make at least enough copies to trade with everyone in the class, give one to us, and one to the library for their rare-book collection (plus more for selling and giving away—however many they want). Then the last class takes on a bit of a party atmosphere, as the students trade and read one-another’s comics.