Hobby development was a lot more fun before I was trying to make full games, when I was just messing around with random tech demos. Sure, there was always some distant goal of eventually turning one of these into a game, but it almost never happened. And I kind of think I should embrace that.
I rambled about jump physics on the TIGS forum throughout the day. Here is a link.
http://forums.tigsource.com/index.php?topic=23143.msg657838#msg657838
I also wrote up some pseudocode for how to easily improve numerical integration with Velocity Verlet here.
http://forums.tigsource.com/index.php?topic=23143.msg658146#msg658146