By Sarah Rodman
9 p.m., Channel 2
It’s already been a tough year emotionally for Lord Grantham and the gang, and Sunday’s season 3 finale-Christmas episode will call for a fresh box of tissues as major life changes are afoot for just about everyone, but especially Lady Mary (Michelle Dockery, pictured) and Matthew, Edith, and Thomas and Jimmy. Hopefully, most viewers have been unspoiled about the big news. If so, pull those tissues closer.
Firefly 8 a.m., Science
If you’ve ever had a friend rhapsodize about Joss Whedon’s magnificent, high-tech-yet-retro space western — cruelly canceled by Fox before its time in 2002 after one truncated, disordered season, and briefly resurrected with the major motion picture “Serenity” in 2005 — now is the time to check it out. The Science channel is airing the series run of 14 episodes starting at 8 a.m., then capping off the night with the hourlong special “Firefly 10th Anniversary: Browncoats Unite,” featuring reminiscences from most of the original cast, including Captain Tightpants himself, Nathan Fillion, now starring on “Castle.” Shiny.
Sports Illustrated: The Making of Swimsuit ’13 8 p.m., Travel
Scantily clad human clothes hangers head to all seven continents.
NBA All-Star Pregame Concert 6 p.m., TNT
Ke$ha, Ludacris, and B.o.B celebrate basketball and nontraditional spelling.
The Amazing Race
8 p.m., Channel 4
Season 22 premiere, let the bickering begin.