Suggestions : The one at the impulse purchase section of your local sex shop will get the job done, but probably won't last too long. You can buy one with an attachment that looks like a little bunny, which gets the job done even cuter.
Another British invention (what is it with the Brits and masturbation?), the Humpus is more than a toy; it's a sex machine. The thing consists of a chargeable base unit to which you attach a silicone ring (or the dildo accessory for the ladies), which the unit then strokes up and down your johnson at anywhere from 80 to 180 strokes per minute. An optional belt allows you to use it hands-free, and a remote gives you—or a partner—the power to speed the stroking action up or down for maximum teasing and pleasure. Let the humpus begin!