Backyard ice rinks are a winter tradition here in Canada. They are tremendously fun, but there are also quite a few risks involved in owning and maintaining a backyard skating rink. The biggest issue here, of course, is the possibility of someone having a bad fall while they're skating or walking across the ice. It's also easy to imagine that an intense game of ice hockey could end with the puck flying through your neighbor's window.
But don't let that dissuade you from turning on the hose and working on those layers of ice. As far as insurance goes, making an ice rink is much the same as having a swimming pool, trampoline, or swing set in your backyard. You won't need any additional coverage outside of your regular homeowner's insurance policy.
Your homeowner's insurance has automatic coverage for legal liability and for medical payments. That means it will step in to compensate the injured party or act to defend you if you get sued (to learn more about your coverage, see Breaking Down Your Homeowner's Insurance Policy, from Coverage A to Coverage E).
But having coverage is one thing. Having enough coverage is another. If you have an ice rink or other equipment or do any activities on your premises that represent a heightened liability risk, you should definitely be reviewing your homeowner's policy's medical payments and legal liability limits with your insurance agent or broker. Chances are, they will recommend that you increase those limits (find out Why You Need a Lot of Liability Coverage – Even if You're Law Abiding).
Those who are particularly risk averse or don't want to expand their homeowner's liability or medical payments limits can instead purchase a separate, standalone umbrella policy. An umbrella policy is a type of liability insurance policy that sits on top of your primary policy(ies). It would step in to pay for damages in excess of those covered under your regular homeowners liability insurance coverage (see Who Needs Umbrella Insurance? to find out if it's right for you).