This is partially out of curiosity, and partly, potentially, useful.
The gist of what I'm looking for is an application (preferably OSX, though it wouldn't be a deal breaker to be Windows or *nix, and preferably free) that would capture MIDI controller data as it entered the computer, whether that be SysEx, channel, system, controller, note on/off, pots, you name it. All of it.
I'm not terribly concerned with the format that the data would be presented. I'm sure it would be interesting however it was presented. I picture, basically, a window that fills up with text (midi data) as I send data through. My guess would be that it parsed out whatever OSX's core Midi software saw.
I am not interested in a large piece of software that "also does MIDI", or has some extra small feature amongst the DAW backdrop. Looking for a small footprint.
tl;dr, The last time I had all of my gear set up, my keyboard controller (an Alesis Q25) kept throwing pitch bend data on its own. I was sure that the data stopped when the controller was unplugged, but I had no way of pinning down exactly what was going on. I eventually gave up.