Riven is a wonderful computer game- the sequel to the phenomenal Myst and the prequel to the extremely wonderful Myst: Exile. It takes a while to finish it, but it's worth it. I would recommend buying a walkthrough book or if you really wanted to figure it out on you own, get a writing pad and draw EVERYTHING that you see. It'll come in handy. Again, it's one of the best games I've ever played!