Question: There was supposedly one episode that ended with SpongeBob, Patrick, Squidward, and Mr. Krabs all laughing in a boat. The laughing then silences, eventually to a stop. Then SpongeBob, Patrick, and Mr. Krabs walk out of the boat, and Squidward eventually walks out too. Which episode is this?
Question: Why would Angel and his friends agree to work with Wolfram and Hart considering that the law firm has been committing atrocities and also been butting heads with Angel Investigations?
Answer: They figured they could root out of the real evil that infects the place and do some good with it. Like an undercover cop that joins the mob underworld.
Question: Why is John's Farscape-1 module able to navigate wormholes where some other, more sophisticated craft, notably Peacekeeper Prowlers, cannot without liquifying passengers?
Chosen answer: It's never explained. John mentions a theory that his less technologically developed craft simply interferes with the wormhole less than the "superior" Vipers, but they never make a concrete determination on that point. But we also have to take into account the fact that Moya traverses wormholes with no ill effect as well.
Question: How did the streetcar, phone booths, and vending machines end up in the digiworld?
Answer: We are never told as to how they got there.
Answer: People who built the digital world most likely had them sent there. Gennai tells the kids in the last episode that the streetcar was from San Francisco, and he asked them to take it back for him.
Answer: I believe this is the Season 6 episode "Spongicus".