Piano Forum

So today was the end of the year concert at my conservatoire, and next week are the last piano classes of the year. I'll be starting university this october, so I won't attend the conservatoire next year, maybe just for a few more lessons.
Anyway, since starting from october I'll be neck deep in my studies (and have much less time to play piano), I want to take on one last big challenge to work on this summer (I want to have it done by September).
I want it to be a piece that's both beautiful and fun to play. It should be technically demanding (right now I'm as good as I'm ever gonna be, so I want to make it count), but I also want to be realistic (e.g as much as I'd like to play Prokofiev's 8th sonata, It's just too difficult, especially for one summer). Just to give an example, last year my summer "challenge" was Debussy's complete "Pour le Piano" suite (Oh boy, that toccata...).
Anyway, any suggestions? Any piece you really like? Was thinking about something romantic/modern.
I'll name some pieces I played this year, just to give you an idea about my level:
- Beethoven - sonata no. 30 (that's what I played at the concert today)
- Beethoven - sonata no. 17 - 1st movement
- Haydn - sonata no. 62 - 1st movement
- Chopin - scherzo no. 2
- Bach - Italian concerto - 3rd movement
- Schumann - sonata no. 2 - 1st movement

Thanks a lot in advance,
Gilad