Eventually, we might run out of topics for the normal challenge. We still have at least 1 year with the current proposals, other proposals can be added and we could also recycle the old ones.
They are called challenge but are not really challenging. I had an idea the other day while browsing the challenge suggestions. I saw several topic with an equal number of votes. I thought that maybe we should could do a challenge with 2 or multiple tags applied together. Questions featured in this challenge will need to cover both topics. Just as an example mythical-creatures and hard-science would be a good combination: Can a supernatural ability be explained with science? It could lead to some very interesting or bizarre combinations and make things more challenging.
This challenge could be set to take part separately form the usual challenge or in alternation.
Note: I used hard-science but it does not have to about specifically about science.