We are basically wanting a walk-around puzzle game built on the theme this year.  Good brainstorming topics are puzzles, visual and mechanical elements, and GUI.

Puzzles:

Conveyor belt death spiral

Groups of blocks that shift left or right on button press, blocking the way to buttons that move other rows(to design work from solved state a la 16 puzzle or rubik's cube).

Everyone's "favorite" push block into spots x y and z.

Floor coloring puzzle.

Do x in order y telegraphed earlier(good for decoding puzzles).

Hidden correct path hinted at by room decorations.

Block a beam with a block.  (Good if demod as a concept earlier and later combined with advanced block moving mechanics)

Blocks that slide until they hit something(stolen from every puzzle game ever)

Timed room changes.

Flickering lights(if we hate our players)

Color combing puzzles(especially doable if you have a mechanic that lets players only affect one color at a time)

Jumping puzzles (combines well with timed changes)

Puzzle involving a secret alternate route to the previous room that allows you to take something from there to the current room.

Series of rooms where you mustgo through the directions you'd have to go in the lost woods in OOT.

Mechanics ideas:

Item x rotates block type y 90 degrees around the player(under certain circumstances).

Item that allows (certain?) blocks to be pushed from a distance when standing on certain squares.

Portals?(Let's not unless it really fits the theme)

One way gates/doors

"Sound waves" can have some interesting behaviors, but probably not worth implementing unless it's perfectly matched to the theme.

Dangerous lasers and projectiles/energy balls.

Optics: mirrors, pointers, beam splitters.  Color shifters?

Before we get too hasty, I want to note that the puzzles should incorporate the theme as much as possible.

• Naturally, but some possibilities can't hurt
• Of course. 

Just a thought I had: We want to maximize people's fun as much as possible.  And when people have a week to judge a whole bunch of games, they aren't as likely to spend as much time on any single game, especially if they get stuck on something.  They may quit out of frustration if a puzzle is too hard for them.  It would probably be a good idea to have some sort of way to skip a level if you get stuck, and maybe to come back to it later.

I like that idea a lot. Not being able to figure one puzzle out shouldn't stop anyone from finishing the game. Perhaps a special room at the end for anyone who completes it with no skips?