In the woods, in parks, in the garden and right around the house, plenty of plants can be observed and admired in the winter. Maybe the most fun comes from identifying them, and noticing their special winter adaptations. On our Backyard Plants page you can get a good start learning about stems & twigs, which have so many distinguishing features that their identities are recognizable during the winter.
It may be worthwhile to do a web search on the keywords "winter botany" or "winter tree identification."