What it sounds like
Frequency grouping, Once-off, radio button, not checked, 1 of 2
This is great because the user knows the name of the group of controls and how many there are. We can visually hide the input and style the label for a different look and feel.
What it looks like
<fieldset>
<legend>Frequency</legend>
<input
class="visuallyhidden"
checked="checked"
type="radio"
id="once-off"
name="repetition"
value="Once-off"
/>
<label class="label-fancy" for="once-off">Once-off</label>
<input
class="visuallyhidden"
type="radio"
id="repeating"
name="repetition"
value="repeating"
/>
<label class="label-fancy" for="repeating">Repeating</label>
</fieldset>