Since I suspect you'll be more than slightly busy tomorrow, I'd like to invoke my birthday trivia tonight:Hit me up with anything Ulgrotha related, and on a side quest, do you think there's any chance the plane might get integrated into Innistrad a la Rath and Dominaria?

While we retroactively made Arabian Nights on Rabiah, Ulgrotha was the first expansion purposefully set on a plane other than Dominaria. It was greatly influenced by the cards from Alpha, the designers thought were popular. We did talk in very early Innistrad design if the plane was supposed to be Ulgrotha, but it had existing elements that didn’t really fit with what we wanted for top-down gothic horror world (like Australian-inspired Minotaur). There’s never been talk of merging Innistrad and Ulgrotha.Happy Birthday!

If I wanted to for some strange reason could I target my opponent with Side Quest?

Sure.

Un-rules question: My cube has some silver border cards, but there's few enough that a player could easily draft an entirely black-border deck without even trying. If two players who drafted such a deck are in one match, could a player in another match send a creature to that game with Side Quest?

A “silver-bordered game” is defined as any game where at least one silver-bordered card is played in at least one deck. If two-players are playing a match your cube and neither one has a silver-bordered card in their deck, you can’t send a creature to them with Side Quest.

Silver-bordered rules question. Side Quest says to send a card to another "silver-bordered game". If I cast Glamerdye to change one color word to another, changing "silver" to "black", can I then affect real black-bordered games of Magic, just to mess with tournament players?

That doesn’t work as there is a meta rule that silver border games can’t mess with black border games.

What if Baron goes on a side quest?

Changing zones restarts him at 5 and the person you give him to only has a turn before he returns, so it’s possible but very difficult.

I asked about GO TO JAIL-ing a creature my opponent received due to a side quest---you gave an answer as if it were a Pacifism effect, but the card isn't an Aura, it's a Banishing Light-style effect. Having read the FAQ, it looks like the creature goes into exile, but does the "at the beginning of the upkeep of the exiled card's owner" trigger happen in the other game? I'm guessing not?

Oops. It’s not an aura. At the beginning of its owner’s turn, they get it back. It doesn’t matter if it’s in exile.

Doesn't your side quest creature return at the start of your turn, before your untap step? That's what the card says, but you guys played it weird on game knights.

At the beginning of your turn it comes back so it untaps. We messed that up on “Game Knights”.

Does side quest trigger ETB abilities? I noticed you didn't compliment each other during Game Knights, after passing Chivalrous Chevalier.

It does. The video was edited down, so small things that don’t really matter don’t appear.

If you're playing a magic subgame (say, with The Countdown Is At One), can you play Side Quest and target your ~*past self*~ in the previous game you set aside?

No, sadly you can’t. The games don’t co-exist.

For a 4 person Unstable draft, do you think breaking into duels or a 4 player multiplayer game would be more interesting?

Whichever your group would enjoy more. I lean towards two games because it would allow cards like Side Quest and things with outside assistance to be used.