Time wasting

I have been sucked into a new way of wasting time. Not that I need much encouragement, my motivation seems to have vanished almost completely. The thing in focus at the moment is www.stumbleupon.com, and i warn you, it is totally addictive. It is mostly a portal to the web, and like many other sites of this nature you can personalise it by noting your own particular interests. By pressing a button - as is often the case, one is randomly steered towards sites of interest, and i have to say that many of them are amazing, though none have been any use whatever at the moment. You know what? i don't really care about that, but I do have to keep going back to look again. I really should do something constructive but I have no ideas right now. Any suggestions??