People in your neighborhood

Lots of famous grown-ups will be stopping by for “Sesame Street’s 50th Anniversary Celebration,” including Elvis Costello, Meghan Trainor, Sterling K. Brown and Itzhak Perlman. Don’t worry; the Muppets also will be on hand to reimagine classic segments and songs like “It’s Not Easy Being Green.” The first episode of the 50th season kicks off next weekend.

6 p.m. Saturday, HBO

Treasure hunt

Justin Fornal and Emiliano Ruprah wasted way too much time in “Unexplained and Unexplored” on the dusty trail when they could have learned just as much by going on the internet. At least that’s the case in the season premiere, in which the two go in search of a massive wooden ship that might be buried below the California desert. What they discover is less than “unbelievable,” despite how many times they utter the word.

9 p.m. Sunday, Science Channel

Space ball

It’s been more than two years since the last “Rick and Morty” misadventure, which makes this new episode somewhat of an event for fans of the animated cult classic. But be prepared for a short road trip. Creators Dan Harmon and Justin Roiland are only unveiling five fresh installments before the end of the year — and just five more in 2020. Enjoy them while you can.

10:30 p.m. Sunday, Adult Swim

Neal Justin