For the LIMS-type of challenges, I believe the only issue with that would be what eotheod was talking about: how if one doesn't participate then the many posts may become excessive or a bother. Then again, a LIMS (in comparison with a Mafia) might be short enough to not get on anyone's nerves.

For the "mod's choice", I believe that's a fair award. Happens all the time in my icontest communities, and it goes over well.

Three challenges at once doesn't seem like much, but when you add it to whatever might be going on in the minigames, a person who likes to do both may feel overwhelmed. I guess in that instance we can just remind them to take it easy and that they don't have to do every single challenge, but I can't help but feel maybe there should be an alteration. Maybe use the lighter challenges whenever something long is happening at the minigames, to compensate those who are crazy participate in both?