Suffice to say, went through a ninja period myself when younger, much younger. Learned some martial arts, etc. but the real interest was in all of the stealthy gadgets. I bought some, made others. Some real neat stuff. Really kind of runs the gambit from magician tricks to spy gear, climbers gear, etc. (and if you really want a real smoke bomb, it's going to involve some pyro. The other ones will not give you enough smoke quickly, to vanish).
If you really want to pull off the vanish trick though, it's MUCH more effective to do it WITHOUT any kind of show. A little bit of misdirection, such as drawing someone's attention elsewhere, for a little time, can give you all the out you need, if you have a planned exit strategy. I disappear like this all the time around my kids, just for fun. (and reappear just as suddenly).
Ninjitsu itself, as a martial art, is more about unconventional warfare and espionage, which is what drew me back then, because I love doing the unexpected, when it comes to tactics (lets face it, it was also big in pop culture too, at the time). Their are traditionally 18 disciplines, but most revolve around a type of weapon...so as a martial art, mostly it is weapons training. The disciplines that are more about tactics, disguise, stealth, water training, horsemanship, etc. aren't likely going to be part of a class you'd take.
The more Ninja specific weapons are always fascinating. Even older and bigger, I'm still a deadly shot with a well made throwing star or well-balanced knife.
- yesterday, we were at the local Ren Fest, and my daughter was holding a staff for a friend, and twirling it around some. I asked her if I could try...and she giggled, and said sure. I then went into a Bruce Lee style display (even older and bigger as I am), that had her jaw drop, it was pretty funny.... I like keeping my kids on their toes.