TV tonight: 'Modern Family,' 'Castle'

Modern Family | ABC, 9 ET/PT
Billy Dee Williams and Lainie Kazan guest in this New Year's-themed repeat, as Jay's plans to celebrate the holiday with his family at a favorite Palm Springs hotel go very much awry -- right up to the point where they right themselves, as they often do on this funny, humane sitcom. As a bonus, the episode also features one of the season's best Cam/Mitchell moments, as they find a novel way to make themselves feel better after the young crowd at a gay bar totally ignores them. So often sitcoms just rehash stories from other sitcoms; finding a plot that's actually new is a rare treat.
Law & Order: UK | BBC America, 9 ET/PT
For those in need of a Law & Order fix, BBC America offers the seventh-season premiere of this British transplant. The show may well be worth watching on its own, but it's most valuable tonight as a viewer-funnel for one of the best series you'll see this summer – and, for that matter, this fall: BBC America's Broadchurch (reviewed here).
Castle | TNT, 10 ET/PT
TNT repeats an unusual episode from February 2012, as the pair's investigation of a present-day murder pull Castle and Beckett into an unsolved case from the '40s -- literally and figuratively, as the stars also play characters involved in the original case. If it reminds some of you of the classic Moonlighting episode that pulled a similar trick, it should – though in this one, nobody sings.