As a safety measure, you should know where your main water and electrical shutoffs are. The water shutoff will be near where the water enters the house. Look for a metal wheel or a flat handle like a paddle. Or check outside for a mini manhole cover—the shutoff may be there. The main electrical switch will be in or near the main box. On an old fuse system, it may be a big lever or a handle that pulls out a whole block. On a modern breaker box it will be an isolated switch near the top of the box. Flip it to keep the circuits (and you, too) from getting fried.
Make sure you know which lever to pull by checking out Know the 4 Emergency Shut-Offs in Your Home