I'm not into resolutions, but challenges and goals tend to motivate me. For example, the goal to complete a 100-mile bike ride. That got me on my bike on days when I was tired or sore or just not feeling it. Generally, my goals will be activity related to keep me working out and in shape.
I didn't set goals for this year, and I may or may not do any big bike rides, choosing to wait until I have a chance to get on my bike in the spring.
Challenges on the other hand...I need to challenge myself to do all kinds of things, and have started with the low-hanging fruit:
Only drink 2 days a week
Writing that down feels like I'm admitting I have a problem. I don't have a problem, other than spending a stupid amount of money at our friendly neighborhood liquor store, and my expanding waistline.