I'm really not a huge fan of being out in the cold.
I know..."So why are you living in Minnesota?" - as if that were the singular characteristic of the state. The simple answer is that I say indoors more in winter, because it is warm there. But, being indoors does limit the photographic subjects available. That means it is time to try something new.
Winter is a good time to experiment with subject, techniques and ideas. If you're like me and prefer shooting in color, try playing around in black and white. If you like landscapes, try macro (and focus-stacking) or still-lifes. Curious what happens if you try a technique in a new way, find out..
Here are some examples from years past:
Probably 15 years ago, I wanted to learn more about printing (this was pre-digital). So, I took a black and white printing class. This is a macro shot of a gerbera daisy.
There are several really nice greenhouses and conservatories in the area. The Minnesota Landscape Arboretum has one, plus they also have an orchid show running now. Those provide a great chance to experiment.
This was a stitched panorama I took several years ago.
Want something more abstract but recognizable, try macro.
Want to try something crazy, go ahead. I knew from previous experience, for instance, that you could get a really interesting effect if you zoom you lens while shooting neon lights (they give you solid streaks of color) So I thought I'd try the same concept on flowers (in these cases, both zooming the lens and simultaneously moving the camera in some way). As you can see, I got some impressions of flowers amidst washes of color. Most of the time the result is garbage, but others can be really interesting.
I'm going to finish this by paraphrasing a quote from Neil Gaiman (actual quote can be found here: http://journal.neilgaiman.com/2011/12/my-new-year-wish.html):
Go you and try something new. Even if it fails spectacularly, you'll learn from the attempt.