Sign up sheets look very similar to checklists, with one major difference:
A checklist is a list of people who all need to do the same thing, like turn in a permission slip. A sign up sheet is a list of a bunch of things that you need volunteers for.
Step One: Create the sign up sheet and invite some volunteers
Go to Communicate -> Sign Up Sheets. If you don't see that option you will need your privileges updated to include sign up sheets.
Step 2: Add some items to the sign up sheet
Once you save your sign up sheet you'll be able to add items to it, like this:
Step 3: Sign Up!
Everyone you've invited to your sign up sheet will have an assignment listed on their "My Assignments" page until the due date is passed. Once they volunteer for an item, that will also show up on their assignments page. Assignments are also included in the newsletter.