Last minute predictions?
Here's mine, with a ridiculous grasp at logic
This morning, we got this picture of the day
This picture shows Pikachu as well as the three different kids of crates, and was teasing the Nintendo Direct tonight.
Typically, each month, we get one or two character reveals. We had zero in the month of March, indicating something big was coming.
Now, each of these crates is different, but in Brawl you could never have each of the crates in one level, but all three are here. Obviously for screenshot purposes, but there could be a hidden meaning.
First, we have an old wooden crate. Perhaps symbolising a veteran. Next to it, a futuristic crate, perhaps symbolising a newcomer and next to that is a present, possibly symbolising something surprising.
Now, the picture could have easily just had the crates in the picture with no character, but on top of the veteran crate is Pikachu, a Pokémon.
So, my ridiculously "logically" concluded speculation
Veteran: Mewtwo
Newcomer: Mii
Surprise: Pac-man
We'll also get the release period and details on the single player and online features.
Yes, I realise my post is ridiculous :p