The dual of meditation = Ashtanga
I will tell you about Ashtanga, the benefits to the mind of which are tremendous. For lack of a tangible point of comparison, I will liken them to Ritalin-on-Speed on a daily basis. I have practiced Ashtanga for 4 years daily. Ashtanga is a "yoga style" but it has little to do with what you have come to know yoga is.
While simplifying the story a little, I will say that Ashtanga is one of two true yoga systems that survive today whose lineage traces back thousands of years into the Indian tradition.
Ashtanga is not very popular in the US, because unlike what we've come to know as the relaxing (and essentially lazy) western yoga, it demands much of you, albeit in return for even more.
It is a "system" (and not a fitness exercise), because it encompasses many aspects ranging from the method of teaching, pose sequences, philosophy of thinking about and maintaining your practice, etc. Every minute detail of Ashtanga (like e.g. the specific sequencing of the poses) has been honed over decades to give you the most effective and gradual entry to a state of physical and mental fitness that everyone, who sees an Ashtanga demonstration, calls "mind-blowing".
Unlike pretty much any other "yoga" in the west, the format of Ashtanga classes is not lead (where everyone performs in sync). Instead, in the Ashtanga room you will see practitioners doing their own sequence (there are different levels) at their own pace and not in sync. The teachers know their students very well and help them at hard poses. Those of you familiar with the psychology of sports will recognize the well-known principle that every individual body and mind learns at a different pace. It is virtually impossible to advance (in pretty much any sport) beyond average unless you work at your own pace, especially at the cruxes.
The benefits:
After having practiced Ashtanga for a month or so. You will start experiencing the good. Right after the morning classes my mind is an extremely high state of focus for about 4 to 5 hours. Years ago, when I first started, I noticed that on my drive back from the studio I involuntarily remember the geometric configuration of cars that I pass (I drive fast) on the high-way for about a half-mile distance. It is a spectacular feeling of mind.
I am only scratching the surface here. A sustained daily practice of Ashtanga keeps your body (all the time) in what doctors call a "sympathetic mode" which is sort of the opposite of what normal people experience in their lives, which is called "para-sympathetic mode". In lamen terms, this means that all chemical process in the body are working at an energetic rate and your brain is constantly "hydrated".
I will stop here. And will give you some references:
The surviving main source of Ashtanga (and the place where all western teachers of Ashtanga go to learn) is the Ashtanga Yoga Institute in Mysore India:
http://kpjayi.org/
You will have to do some work to find Ashtanga near you. Use the Internet. These studios are somewhat clandestine due to the low overall demand.
I will give you a link to an Ashtanga demonstration on YouTube. Before you view it, remember this: Unlike most other yoga teaching systems, regular students of Ashtanga who are not natural-born athletes and don't even have athletic builds can achieve and do achieve what you will see in this video:
http://www.youtube.com/watch?v=1UcIn2W6ghw