...I'd wager that you most likely deserved to be capped. Or cut off. Probably serving and/or downloading stuff that you're (a) not supposed to under general ISP TOS provisions/copyright laws or (b) that's taxing a network resource in your local area. Turn off the PC, go outside, and look at that lovely thing called the sun every once in awhile and you'll keep Comcast (or your ISP) off your back.
P.S. - Seriously -- they're just trying to get you outside and reasonably tanned. Part of their public image plan. -- Desktop: Abit KG7-RAID | AMD AthlonXP 1800+ | 512MB PC2100 DDR | 128MB ATI Radeon 9500 Pro Laptop: Dell Latitude C810 | Intel PIII-M | 512MB PC133 SDRAM | 32MB Nvidia GeForce2 Go