I did dress up as Shen from the original Dragonball once, but I dress like him normally every day...

But no, I haven't really cosplayed. I guess it could be fun, as long as you don't go all obsessive and are all 'in-character' mode. It doesn't have to be a big deal... There are some wonderful cosplays I've seen, and not just as Rydia*.

*Shaaaads!