I've set a competition in today's Guardian for young writers in the UK between the ages of 5 and 16, with some very good prizes.  It's in the Comics page in the Family section, check it out.

I've provided the opening and closing lines, so the young people who enter have to connect the dots in the most interesting and thrilling way.  I get to judge the winner personally, so this ought to be fun.  Good luck!

(Again, though, note the age requirement and that it's for UK residents only (sorry, America and Australia, but I'm working on it...))