Still looking for a gift for Dad for Father's Day? Zazzle.com is offering 50% off Light Apparel ('no dark apparel, embroidered products, screen printing or shoes') when you use the code "LIGHTAPPAREL" through 11:59pm PT today! They have some really great t-shirts - ranging from sweet to hilarious (*all kinds of humor!)
You can get an even better deal though if you go through a cashback site to make your purchase! Ebates is offering 10% back (and possibly an extra 12% off!), and Mr. Rebates and ShopAtHome both are offering 15% back! If you're new to any of those, they give you a $5 credit in your account as a bonus to sign up! That could mean a super cheap shirt for dad!
*You can also get 50% off 2-day shipping today with the code SHIP4FATHERS (not sure if two codes can be used or not