I am an enthusiast myself, for me it is both a hobby and also a way to protect myself.
So, to all here, do you practice any, have studied any?
For me, I've done combat sambo back in the military; and then I also tried Wing Chun. It is a Chinese martial art, a sub-style of Kung Fu, is very popular in Russia, we have 8 large schools in Moscow, Petersburg, Yaroslavl, Chelyabinsk, Irkutsk and Novosibirsk.
It is my favorite system, so far. Involves a lot of work with hands (which is why also known, here at least, as 'Chinese boxing').
It's main premise is striking the center of the body.

That is what makes it effective: you strike at most vulnerable, and sensitive areas, like face, throat, solar plexus, groin.
No, I cannot do
this quite yet lol [ame="http://www.youtube.com/watch?v=EsGH4LHslhg"]YouTube - Π’ΠΈΠ½ Π§ΡƒΠ½ ΠšΡƒΠ½Π³ Π€Ρƒ. Π”Π²ΠΈΠΆΠ΅Π½ΠΈΡ Π½Π΅ ΡƒΡΠΊΠΎΡ€Π΅Π½Ρ‹!!![/ame]
That's Spartak Petrosian, he is a Master. Has his own school.
I also did some Izvor, which is a indegenous Russian combat art that is, actually, quite similar to Wing Chun and to Kung Fu in general.
It is a street-fighting system developed by Dukhobors in the North to defend themselves against Orthodox Christian traditionalist extremists who constantly attacked and harrassed them (this was way back, when the Tsars were still in power): [ame="http://www.youtube.com/watch?v=vfBMJwCbEHg"]YouTube - Π˜Π—Π’ΠžΠ* Ρ€ΡƒΡΡΠΊΠΈΠΉ Ρ€ΡƒΠΊΠΎΠΏΠ°ΡˆΠ½Ρ‹ΠΉ Π±ΠΎΠΉ[/ame]
Used today by Specnaz units, including with Systema Kadochnikova (which is itself partially based on it).
Basically, I like these two as they are practical, not just for sport, for fun, at the gym, but to defend self on the street. Both are good for fighting people who are bigger than you, or against multiple opponents.