Companies are taking some tips from video-game designers to create more alluring products and advertising. Doritos (PEP) and Hilton's Embassy Suites are enticing customers to play games in marketing and branding campaigns. Nike (NKE) and Nissan (7201:JP) are using elements of game play to make their products more compelling. Google (GOOG), Target (TGT), and other companies use game elements such as scoring and rewards to make mundane tasks more interesting for workers. Read on to see how it's done.