A friend of mine has a rather precocious daughter with poor impulse control, and asked if I knew any behavior games that encourage children to think out the consequences of actions before they do them.
I'm familiar with the Good Behavior Game and the like, but standard conditioning hasn't been very effective with this child in the past. She's quite clever about subverting rules when possible, and shutting down entirely when subversion fails.
Please, one suggestion per thread so that the karma thing can do its thing.
In my experience, problems with conditioning / behaviorist interventions often arise because the function of the behavior is not well understood. Before you work too hard on designing interventions, I suggest thinking a bit more about the function (aka purpose) of the behavior.
For example, a toddler who tantrums because he doesn't want to get dressed and a toddler who tantrums because he doesn't get the sweet might perform similar behaviors. But the functions are totally different - my first example has a function of escape from task demand, while the second function is receiving a tangible object.
Until you have a good grip on the function of the behavior (and this can be very difficult), any intervention to change the frequency of a behavior is hit-or-miss at best. Some more discussion of function of behavior (in the context of autism) here.
Also, if the child is intellectually precocious, this doesn't mean that her other functional skills (mood management, etc) are also advanced. There is a limit about how much a parent should reasonably stress out about skill limitations that are developmentally normal.