I don't know about other people but with Blitz I just sit down and start writing code as I brainstorm. It's seriously like poetry ... very free form.
I actually program in blitz to releive stress, So I know what you mean. However, that usually means my code is a peice of turd. An efficient one, but a peice of turd non the less :)
I do like ODE- I've taken a look at the in-house physics and it doesnt look hard at all to set up- I may have to find somewhere in source to add some more gravity though ^.^ No to moon buggies!
If an in-house ODE solution pops along, I'd be jumping for it :D