gistfile1.txt

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.[]
Extracted source (around line #45):

42:         .entry
43:           .calc
44:             %p.label Closed Deals
45:             %p.value #{number_with_delimiter @data.deals_closed_for(period)}
46:             %p.chang=display_percent(@data.deals_closed_percent(period))
47:           .calc
48:             %p.label Coupons Purchased
Rails.root: /Users/santiago/Projects/groupBuying

Application Trace | Framework Trace | Full Trace
app/models/site_info.rb:36:in `deals_closed_for'
app/views/sites/show.html.haml:45:in `_app_views_sites_show_html_haml__225209490_2211440000_0'
app/views/sites/show.html.haml:40:in `each'
app/views/sites/show.html.haml:40:in `_app_views_sites_show_html_haml__225209490_2211440000_0'
app/controllers/sites_controller.rb:24:in `show'