If the discount start date is set to a future date the discount will not be accessible until that date. If the discount end date is today's date, the discount is already expired.

Steps to Reproduce

1. Create the discount code: Control > Code Library > Discount Codes > Click New
2. Apply the Discount Code: Communities > Special Events > Friends Asking Friends > Kintera Thon > Manage event name
3. Fee Structure > Click Discount next to the registration type you want to apply the discount to
4. Enter Discount info with Valid from 03/01/2014 to today's date
5. Select a Discount Code and a Discount Value
6. Click Add > Observe the Valid Dates. It says 03/01/2014 - Today's date
7. Now test it by going to the frontpage of the form
8. Click Register Here and fill out all the required info
Observe: There is no discount code available
9. Now go back and change the end date to tomorrow and it will appear