Starting January 1...

...portions of the Affordable Care Act will kick in. A tax on health insurers will commence; Medicare Advantage programs will have to spend at least 85% of their subscriber premiums on actual medical costs, as opposed to administration and profits; and employers will be permitted to tie as much as 50% of their employees' insurance costs to their participation in various wellness programs- 30% for general wellness, or 50% for programs aimed at quitting tobacco.
...the Boy Scouts will accept gays.
...40- and 60-watt incandescent light bulbs will no longer be available.
...Colorado will see the first state-licensed marijuana retailers open.
...13 states will raise (PDF) their minimum wages; 1,441,000 workers nationwide are currently paid salaries below their new respective minimums and will therefore get automatic raises, and 1,122,000 additional workers stand to get raises through restructuring of employer payscales. The largest increase is in New Jersey, going from the federal minimum of $7.25 to $8.25. New York will also decouple themselves from the federal minimum, rising to $8.00.
...you will no longer be able to smoke on the campus of San Diego St.
...Los Angeles will ban grocery chains from using plastic bags.
...residents of Albemarle County, North Carolina with junked cars on their property must completely cover or screen them so that neighbors cannot see them. Tarps are not acceptable.
...new mothers in Oregon can take the placenta home if they want.
...fracking operations in California will be required to disclose, to a certain extent, what chemicals they're using during the process.
...Illinois' speed limit will tick up from 65 mph to 70 mph. Using your cell phone while driving will also become illegal.
...Australian workers who believe themselves the victim of bullying in the workplace may apply to the federal Fair Work Commission to seek redress.
...Latvia will join the eurozone. Most Latvians aren't happy about it.
...you will note that you didn't even bother to make a resolution this year because you're just going to break it anyway.