Depending on where you live. I live in the NorthEast and I personally cannot have a meaningful/productive training at 20F and below.

As for boredom just get lots of CTS or Spinerval videos. The only time I put a regular show on was for easy spin days but otherwise Spinervals/CTS videos will whip your butt.

Buy a quality trainer like the Kurt Road Machine or Cycleops Fluid 2. Never settle for anything less than those 2.