It's time to play a bit more catch up.
Day 12 - What game is your group most likely to play next?
This is another of those questions that simple seems to assume that gamers only have a single group with whom they game. I see that this is not the case for a lot of individuals I know across the gaming sphere, because a lot of people seem to do "online hangout games" as well as "physical" games. Similarly, plenty of people I know (both online and locally), have home games as well as games that they are a part of in a gaming store.
I know (and have been a part of) gaming groups who have played the same campaign for decades, for whom the idea of a new game system is the ultimate heresy...conversely I know (and have been a part of) gaming groups who regularly shift games every few weeks to try a wide diversity of gaming experience.
In my experience, this seems like a really odd question. I can understand how certain gamers might look at this question and assume everyone has the same gaming experience, but my experience (and that of many people I know) doesn't really gel with it.
Since I tend to be the "default GM" in many of the groups I'm a part of, the simplest answer to this question might be... "Whatever game I decide to run next!". In this case, the game I'd most likely see in play next would be one of the games I've been working on that requires a new round of heavy playtesting. Probably "Familiar" or "Walkabout".
Day 13 - What makes a successful campaign?
I feel we've touched on this one earlier, especially with Day 9's question "Beyond the game, what's involved in an ideal session?".
Another perspective here might be useful.
I think a good campaign is defined by a good ending. This is one of the regular features that seems common among the games I remember fondly, while many of the other games I've been a part of have either fizzled out, or had a dramatically bad ending.
For these purposes, a good campaign needs to have reasonably complete story arcs for all the characters before winding up to a group climax, or winding down deliberately to allow the characters to go their separate ways once the intertwined narrative has reached it's conclusion. Yes, characters may die along the way, before their narrative is resolved...yes, new characters might come along, and might not get the chance to be explored and detailed as much as the others, but as long as everyone feels significant steps of growth as individuals, then I feel that has been a successful experience.