So, leaving the bit about my imagination out of the equation, the simplest facts seem to be this:
Based on the contents of the note we all received, someone or a group of someones appear to be in possession of something in the range of fifteen to twenty of these clocks, which based on other things I've seen on the forums, the people who did some research, seem to be somewhat old and rare collectors' pieces at this point. They have dismantled the clocks (presumably ruining their value) and somehow imbued them to grant the ability to witness one's own personal memories when reassembled, as if this [...] ability is keyed to each person who received a piece. Then, they selected somewhere from sixty to eighty forum users to receive these pieces, knowing that we would take to the forums to discern who had which pieces and colors. Not everyone from my group has come forward yet, so incomplete data there. I think the individual conditions can be broken down a bit further, though:
Likely: Finding the names and home addresses of forum users in order to send the clock pieces Unlikely: Owning fifteen to twenty rare and valuable timepieces, all in different colors, and then proceeding to take them apart and ensuring that this little [...] exercise, or whatever has a cost in the seven-digit range Improbable: These objects will grant the user the ability to relive one of their memories. I haven't seen anyone report back on the forums that their group has put one together and experienced this. However, based on this past spring, I can't categorize this as impossible, as much as I want to.
But that's just everything I know. I don't have a hypothesis at this point because if the improbable part hits as true I suppose the rest of it becomes increasingly likely.