How to entertain 7 year old and 12 year old I'm babysitting? HELP PLEASE!!!?

i let them watch a movie already, and they ate. i have no idea what to do now! they are currently watching a planet earth episode on oceans, but i have no idea what to do when they are done in a half hour! HELP LEASE they didn't bring anything to do, my yard is filled almost a meter up with snow, its cold outside, and i don't have cable tv. they don't really like games like charades, its awkward. PLEASE HEp IF YOU CAN WHAT CAN I DO?