Heres mine:

easy: 1. go on a murderous ramage
2. find a place were life is exactley how you want it

hard: kill your dark side.

destroy the universe.

meet your subconcious mind and ask it questions like "what is the meaning
of life."

battle an extremely powerful dream character, with any weapon you can
think of, with the universe as your battleground.

near to immpossible : make a shared lucid dream by pulling people that you
know out of there dreams and into yours and hang out.

enter other peoples dreams and scare them, like freddy Kruger

WARNING i have no idea if these are possible, but if you can do it congratulations, and the second impossible task could backfire on and could cause the other person full lucidity and control of there dreams, which could cause you to fight for your lucidity, and on that note:

Greatest task ever: Have a shared lucid dream, where you fight your friend or enemy with the universe as your battleground.