Ever had difficulty removing rust from a household object? The solution to this problem might be right in your fridge. Boingboing contributor Jacob Weisberger successfully used Coke to clean rust that had accumulated on his prized 1975 BMW motorcycle's tool kit. All it took was a quick 15-minute dip in a bowl of undiluted Coca-Cola (and a little elbow grease) and his tools lost most of their rusty buildup. I look forward to trying this trick myself to remove some rust spots from an otherwise lovely pasta-straining pot of mine. Perhaps it's just the right purpose for that flat bottle of Coke lingering in the back of the fridge from a party two months ago.
You may have also heard that Coca-Cola or other sodas can literally dissolve your teeth (for example, if you were to leave a baby tooth in a glass of the sweet beverage overnight). As Snopes explains, that's (fortunately?) a myth: Coca-Cola will not dissolve teeth (and, even if it did, so would many other acidic but healthy-ish beverages like fruit juices).
For the same reason that the brown bubbly cleaned the tools well, though, you can also use Coca-Cola to clean a toilet. The several acids contained therein will help to dislodge toilet stains for easier follow-up brushing. I wouldn't suggest buying soda with this purpose in mind, however: you may be tempted to drink the Coca-Cola instead of cleaning with it, but you sure won't be tempted to drink an ordinary bottle of Lysol.
There are a number of additional household uses for Coca-Cola — some seem fairly dubious. But basically anything you do with your soda will be ultimately better for you than consuming it (unless diabetes, obesity, gout, heart disease, and decreased bone density are your goal).