There's a limit of one "deal" coupon per person. You can use the coupon anytime between now and April 3, 2013, but you only have until 11:59 p.m. on December 8 (2012) to take advantage of the Groupon deal.
If you're not familiar with Groupon, they offer a new Northeast Ohio discount each day. If enough people purchase the special, then everyone gets the discount. Like today's offer, most represent a significant savings. To learn more about Groupon or to participate in today's offer, click here.