Extended Level Playlist

We have lots of great levels on the forum. Unfortunately, they are in the wrong order for a new player. The older, simpler puzzles are buried deep, and the puzzles on the front page of the 'custom puzzle levels' forum often require a considerable amount of experience to solve. As a result, few new players enter the community.

I suggest we collect together a list of our best puzzles, in the approximate order in which they should be tackled by a player who has just finished the built-in levels.

What I have so far, in order:
Kevan's Random-to-random matching (lygofog)*^
MagiMaster's Passing Trains series (mahytoh, celalal, pidugos, fysoxih, domedyg )*

*needs updating to the new physics model
^needs an exploit fixed