$form['option_occassions'] =
array(
'#type' => 'checkboxes',
'#title' =>
t('Associated Occassions'),
1 => "Formal",
2 => "Social",
3 => "Xmas",
4 => "Hens",
5 => "14th Birthday",
6 => "15th Birthday",
7 => "16th Birthday",
8 => "17th Birthday",
9 => "18th Birthday",
10 => "21st Birthday",
11 => "20 Something Birthday",
12 => "30 Something Birthday",
13 => "40 Something Birthday",
14 => "50 Something Birthday",
15 => "60 Soemthing Birthday",
),
'#multiple' => true,
'#default_value' =>
array(
1 => 4,
),
);