MacScan is offering their anti-spyware program for free. All you have to do is download and run the 5.1MB installer. When prompted, click 'purchase macscan' and enter the coupon code 'PIRATE' during checkout.
The download, install, purchase and registration must all be completed by Monday, September 20th 2010 by midnight PST.
I am not a fan of Talk Like a Pirate day, but I am a fan of getting stuff for free. The software normally costs US$29.99.
The subject of whether or not Mac users need to run anti-virus/anti-spyware software is a perpetual debate, with one side saying all you need is common sense and another side saying you can't be too careful. If you're in the latter camp, here's your chance to add security to your Mac for free.
Since this is a "talk like a pirate day"-related post, I think I'm contractually obligated to include at least one sounds-like-a-pirate word. So..."Djibouti." There. Happy now?
Update: several commenters point out that if you are not located in the USA, be sure to change the costs on the checkout page to US Dollars or it ends up costing $0.01.