* GAME OF THRONES. 9 p.m. Sunday, HBO.

No longer just one of the most-watched shows on premium cable, "Thrones" this season has become one of the most-watched TV shows on Sunday, period. This week's episode, "The Bear and the Maiden Fair," was written by George R.R. Martin, on whose books the series is based.

* ULTIMATE SURVIVAL ALASKA. 10 p.m. Sunday, NatGeoTV. Moves to 9 p.m. starting May 19.

Can't get enough of Alaska shows? This one takes eight experts in extreme survival - ranging in age from 26 to 57 - on an expedition where the goal, according to the network, " is to make it out alive, using just the gear they can carry in their packs.

* FAMILY TREE. 10:30 p.m. Sunday, HBO.

Fans of Christopher Guest ("Best in Show," "Waiting for Guffman") should welcome the chance to see his latest venture, a semi-improvisational comedy about a slightly lost man named Tom Chadwick (Chris O'Dowd, "Girls") who embarks on a search for his roots after a relative leaves him a trunk full of mementos.

"Family Tree" was inspired by Guest's own genealogical explorations and makes use of his unofficial repertory company, including Michael McKean, Jim Piddock, Ed Begley Jr. and Guest himself as cousins.