Dungeons and Dragons.

[shiznitz]

Lost Caverns of Tsojcanth. Yeah, I said that shit.

No you didn't because it is unpronounceable.

[Ingmar]

You guys are thinking too small.  "Expedition to the Barrier Peaks" would make a perfect JJ Abrams movie.

Weird-ass clues that lead nowhere - check
Big CGI-able critter in the middle for a chase scene - check
and at the end when the party gets tossed back into daylight ... LENSFLARE.

Was that the one that ended up with laser guns or something? If not, which one am I thinking of?

Correct. S3, spaceship dungeon crawl with all the colored key cards, etc.

[Trippy]

Metamorphosis Alpha cross over! Loved that game.

[Surlyboi]

You guys are thinking too small.  "Expedition to the Barrier Peaks" would make a perfect JJ Abrams movie.

Weird-ass clues that lead nowhere - check
Big CGI-able critter in the middle for a chase scene - check
and at the end when the party gets tossed back into daylight ... LENSFLARE.

Was that the one that ended up with laser guns or something? If not, which one am I thinking of?

Correct. S3, spaceship dungeon crawl with all the colored key cards, etc.

Yup. That was the one. My players were all non-plussed because half of 'em were already packing plasma rifles from the Gamma World crossover I'd done previously.

[Tannhauser]

Do the A series. 

-Obviously bad guys (slavers)
-Interesting locales (Highport, Suderham, a country ruled by evil, a volcano)
-Intrigue in the streets of Suderham
-Heroes get stripped of their gear, have to fight the Slave Lords as the volcano blows

Book it, done.

Close Second:  Hommlet/Temple of Elemental Evil

[shiznitz]

White Plume Mountain wouldn't be bad either.  The tech now exists to do the giant crab well.  And Blackrazor is the best DnD magic weapon ever published, followed closely by Wave, the trident in the same module that devastatingly sucks the water from your body on a hit.