You could also give them all the same name so they are an array, but give them different values:
<div id="checkboxes">
<input type="checkbox" name="c_n[]" value="c_n_0" checked="checked" />Option 1
<input type="checkbox" name="c_n[]" value="c_n_1" />Option 2
<input type="checkbox" name="c_n[]" value="c_n_2" />Option 3
<input type="checkbox" name="c_n[]" value="c_n_3" checked="checked" />Option 4
</div>
You can then get only the value of only the ticked ones using map:
$('#checkboxes input:checked[name="c_n[]"]')
.map(function () { return $(this).val(); }).get()