Some of you may know already, but Project M is a mod for Super Smash Bros. Brawl to make the game mechanics more like Melee. It brings back wavedashing, L-canceling, SHFFLing, COMBOS, and all those other physics we had in Melee (and no more tripping, yay). Of course, it doesn't perfectly emulate the Melee engine, but it still does a pretty good job in my opinion. Characters have been "meelified", but its still in its beta stages, so some characters like Meta Knight and Olimar are not included in the beta yet.

For more information:
http://projectm.dantarion.com/
And search Project M on google.

Personally, I really like it.
For those who tried or for those who just want to make first impressions, thoughts?