Groupon is a website that offers deep discounted coupons for various services every day. The GLSEN promotion is part of Groupon's charity program; so in this case a $10 donation is doubled to $20 by an anonymous donor.

GLSEN Deal of the Day | Grouponwww.groupon.com
If 250 People Donate $10, Then GLSEN Can Provide 250 LGBT Resource Kits to Middle and High Schools