SpeeDefrag is an offline defragging utility that is blindingly fast. Once you install it, whenever you click on it a small window pops up with drive designations, then you pick the drives you want defragmented and then press ok. Your computer restarts and prompts you for your password, then before anything is loaded it starts defragging, it is incredibly fast due to this lack of overhead. Once it is finished it turns off your computer. Its really awesome, an absolute must have for anyone that uses their computer on a regular basis. Its original site is here.
Download it directly from this site here.