Hanging lights on branches. Go natural with a fat branch and hang a combination of ornaments and candles attached with wire. Use twine or strong fishing wire to suspend the branch from above. You might want to try hangers so as not to damage your ceiling.
Cutest office gift ever: Hearts & hyacinths. "forced" bulbs for the holidays. Amaryllis with white hyacinth & red tulips in a clear container with just stones and water, no dirt. Then tie a beautiful ribbon around it.