Lots of people are suggesting you buy a firearm if you get a rebate. There are numerous suggestions (partial listing):
I have another suggestion and I'll even make the deal sweeter for you. Buy a rifle and ammo for Boomershoot and I'll give you a free entry into Boomershoot 2009. Limit of one entry per rifle and no more than five free positions will be given away. You must purchase the rifle between now and June 1, 2008. The rifle and ammo must be capable of at least regularly connecting with the boomers at the 375 yard line. This means your ordinary hunting rifle, carbines, and pistol caliber rifles won't qualify. Heavy barrel AR-15's will. It should have at least a 4X (10X or greater is recommended) scope on it but I won't be holding that against you because people have connected with red-dots and iron sights, it's just not easy. Ammo is going to have to be match grade.
If you decide you want to participate in Joe's evil plan then scan a copy of your receipts, send the scanned image and one or more pictures of you new rifle to me. First come, first serve, limit five prizes total.
Update: At the suggestion of Mopar in comments I've created a Boomershoot web page on rifle selection and threw in a little about ammo too. See also Choosing Optics (from 2001).