Take the blue pencil sharpener to the rubbish bin.
The coffee cup is there.

The reward for one of the puzzles (I forget which) is
a sketch of the gang on their way to the "Draco Duel"

Which Peeves did you get?
The reward for dialing his name is a sketch of Peeves.
Also, somewhere in this club someone said he appears in
two places and you're supposed to catch him or something.
I think one is the main desk top. I haven't seen him.