Ends 10/1 at 10PM PT. Shirt.woot! is taking 40% off T-Shirts and other apparel (no minimum order) with coupon code SPOOKYSHIRTS [Exp 10/1]. Shipping is free with Amazon Prime (make sure to sign in with your Amazon account when prompted), otherwise $6.

They have tons and tons of geeky and pop culture designs. Check out Top 20 Designs and Bestselling Designs. Here's a few curated sales as well:

• Halloween T-Shirts
• Bargain Shirts! ($13 Shirts)
• Product Parody Apparel!