Planning a big trip in the new year? Someplace, I dunno, kinda hilly and foggy? If you're bringing along spare batteries for your laptop, take note of new FAA regulations starting January 1: lithium batteries, such as the Li-ion packs that power the MacBook Pro, are no longer permitted in checked baggage due to a remote risk of fire. Two extra batteries may be carried in carry-on luggage, but spares should be packed in individual clear plastic bags to reduce the short-circuit risk; the FAA also has other tips for safe packing.
While I understand that the FAA has to err on the side of caution, this restriction seems faintly ridiculous to me. Still, if you're not in the mood to argue with TSA staff when you travel (never a good idea), there are always alternatives.