Executive functions (EFs; e.g., reasoning, working memory, and self-control) can be improved. Good news indeed, since EFs are critical for school and job success and for mental and physical health. Various activities appear to improve children's EFs. The best evidence exists for computer-based training, traditional martial arts, and two school curricula. Weaker evidence, though strong enough to pass peer review, exists for aerobics, yoga, mindfulness, and other school curricula. Here I address what can be learned from the research thus far, including that EFs need to be progressively challenged as children improve and that repeated practice is key. Children devote time and effort to activities they love; therefore, EF interventions might use children's motivation to advantage. Focusing narrowly on EFs or aerobic activity alone appears not to be as efficacious in improving EFs as also addressing children's emotional, social, and character development (as do martial arts, yoga, and curricula shown to improve EFs). Children with poorer EFs benefit more from training; hence, training might provide them an opportunity to "catch up" with their peers and not be left behind. Remaining questions include how long benefits of EF training last and who benefits most from which activities.