So here's how a Comic Makeover works:
Find an old comic book (look online too) with a short story with 2 to 4 characters (two main characters and X number of side characters works great) that's about 3 or 4 pages long. The tackier the story the better, Romance Stories work great for this.
Next convert all the art EXCEPT the boarders, word balloons and text to blue line art (see example below).
Once you have your Blueline sheets, print a bunch of those out keeping the blue fairly light (lighter than this sample), Two or three artist can work on a single story or if there is time everyone can do a full story on their own.
Now comes the fun part ...
Don't tell anyone what the story is or what it's about!
Just tell them they need to design some characters (character's theme can be anything, cats, robots, monsters, whatever) as long as they are simple enough to do a four page story in the time you have. If you have lots of artist, one person can design the characters, one can do the pencils and one can do the final inking so it's a fun colaboration.
Now that they have characters it's time to give them the story sheets and let them workout how thier characters are going to play out within the layouts of the blueline sheets (backgrounds can be altered to fit in with characters better if you want).
The Finished Project:
Below is and example of how Brian, Jeff and I came up with some characters for the story above and then shared pencil and inking duties, Enjoy!
(Clicking images will enlarge them for easier reading)