Maybe a fun one would be to summarize what evolution is and give some examples of adaptations by species, then hypothesize what some adaptations our species might make given the current 'modern' way of life. Just make the assumption that we continue to live the same way for the next ten thousand year.
Just remember its not about 'useful' or 'good' ..Its all about passing on genes. The movie Idiocrasy takes a negative (but really funny) view on that subject, it might inspire you.
I linked you to a listverse article on '8 examples of evolution in action'