Keep as many bagels out as you plan to eat over the next day and prepare the rest for freezing.
One option is to slice the bagels first and place them in a plastic bag (freezer bags are preferable) to freeze them. This allows you to take out a pre-sliced bagel and place it directly in the toaster (our bagels toast well directly from the freezer).
A second option is to place the unsliced bagels in a plastic bag and freeze them. Some bagel connoisseurs believe that this better seals in the moisture within the bagel.