ThinkGeek offers this Tingling Electronic Spidey Sense Motion Detector T-Shirt for $4.99. Coupon code "FIFTHOFF" cuts it to $3.99. With $6.04 for shipping, that's $36 off and the lowest total price we could find. It features a clip-on motion sensor with vibration motor (which detects motion up to five feet away) and comes in sizes S through XXL. Deal ends April 13.