http://rosettacode.org/wiki/Runge-Kutta_method#using_lambda
It does not look as bad as one might expect, though the nesting of parenthesis makes things messy.
You can't get context managers or exception handling (although you can raise exceptions) into lambdas, I've tried.
def apply_ctx(ctx, func, *func_args, **func_kwargs): with ctx as __ctx: func(*func_args, **func_kwargs, ctx=__ctx)
No disagreement, really depends whether you're a "rules" or "spirit" kind of person though.