Remember the time Capt. Picard met up with Dracula? If you can't, don't worry. It wasn't because you missed an episode of Star Trek: The Next Generation. It's because you weren't paying close enough attention to Sesame Street, the classic kids' show now celebrating its 40th birthday, which was often as science-fictional as it was educational.

Here are some of our favorite sci-fi moments from four decades of Sesame Street.

---

Patrick Stewart Helps the Count

When Number One won't behave, who better to call on than Patrick Stewart? The man behind Capt. Picard visits Sesame Street to help the Count "Make it so."

---

Spaceship Surprise

The crew of Spaceship Surprise had a mission to "travel through space in search of new stars and planets." It wasn't quite a five-year mission, but it was certainly filled with ... surprise.

---

Ernie and Bert Meet the Martians

When gullible Ernie thought cynical Bert had been abducted by Martians, it seemed like The X-Files all over again.

---

Prairie and Elmo in Space

Some of us grew so annoyed by the nonstop giggling of Tickle Me Elmo that we wished we could send him to space. Only now that he's up there, Prairie Dawn wishes he'd stop annoying her.

---

Old MacDonald Had a Spaceship

Not content to torment Bert and Ernie, the Yip Yips land their spaceship to go after Kermit ... and mangle a classic children's song as well.

---

A in Space

An astronaut teaches the first letter of the alphabet while using what's now become an embarrassingly antique computer.

---

R2-D2 and C-3PO on Sesame Street

C-3PO counsels R2-D2 about the love that dare not speak its name ...

---

V in Space

The suits at ABC may tell you that they remade an old TV series for their show V, but we think they really took their inspiration from this early Sesame Street clip.

---

The Count's Rocket Ship

For the Count, the countdown is the best part of any launch.

---

Spaceship Surprise: The Next Generation

A starship crew—including a Muppetized Picard and Worf—lands on the Planet H.

---

Buzz Aldrin Talks About Space

The second person to set foot on the moon pays a visit to inspire the next generation of astronauts.

---

A little boy gives direction to an alien

When an extraterrestrial gets lost, a small boy shows him the way to his mother's UFO.

---

Neil Patrick Harris Has Telly's New Shoes

Dr. Horrible sings and dances as an angelic shoe salesman. Is there anything this guy can't do?

---

Christopher Reeve Talks About His Wheelchair

In one of the show's most powerful clips, Christopher Reeve, the man behind Superman, visited Sesame Street to spread understanding for the differently abled.

---

Natalie Portman Decides to Be an Elephant Instead of a Princess

If Portman had only worn that elephant suit for her role as Princess Padmé Amidala in the Star Wars prequels, we'd have enjoyed them a whole lot more.

---

And if we missed any of your favorite Sesame Street sci-fi moments, let us know!