Bukkit

Added:
FireFlower (Rose)
Stigularity Grenade (Enderpearl)
Shoot Firecharges on rightclick

KnockBack system (XP level is your knockback level as well)
Awesome Particle effects
falling blocks
flying blocks
block physics
Various bug fixes
When DancingWalrus joins, it will annouce "[my IGN] Creator of Smash has joined the server!"

And more!

None.
Lots of errors on "Could not pass entity blah blah" Don't post that error please, I know about it, it's just because Minecraft is not used to doublejumping people..