You know on Facebook there are so many groups with the group creator(s) saying if a certain number of people join the group, they would do something: maybe renovate a house into a pirate ship, shave his head off, dance in public etc. Should this be considered a meme?
There's also another type of group called "I bet I can find X people (within Y time) who like/hate Z". Maybe this can also be a meme?