Do you think there is a way to find a club, who sponsors me for the VISA application? (I am from Hungary)
I am ready to challenge myself in the USA as an aerobic instructor. I speak English and German. I have 11 Gymsticks (fitness tool from Finnland - very good), and I would like to hold classes with those, but I have certification for many other class types as well (Body Balance, Kangoo Jumps, Cardio KickBox, Total Body Cardio..)
Coming to US for work without any type of VISA before hand it's not a wise idea. It's very difficult to obtain a working permit in the United States, unless you posses a very rare specialty that doesn't exist here or it's very difficult to find. US immigration laws are very strict. Most local gyms will prefer not to deal with Immigration and Naturalization Department and they will not go thru the hassle to sponsor working visas to foreigners, since they can find what they need here in the US. If you are in the US right now, you could try to contact gyms that you are interested working at, but in my opinion it will be hard for you to stay and work if you don't have a working permit right now.
I saw in your profile that you have done some work in Greece. I know there are many places back home where professionals like you offer similar classes and trips. Since you are European, I would suggest to look for places around EU to teach, since it's a lot easier to get hired there than here. There are many websites that post fitness opportunities for those who are interested working in Europe. United Kingdom alone has many opportunities available and since you speak German I would also look into Germany, Austria and Switzerland (they pay big $$ for people in the fitness industry). I hope this helps.
I saw your comment to Harris. I speak from the perspective of somebody who has gone through the immigration process.
I understand your desire to stay in the United States. Be aware, though, that violating US customs and immigration laws as you are trying to find a sponsor can get you into really hot water and will not help your case if and when you find one. I am sure you know that the only other way to obtain legal status is through marriage.
You can speak with an attorney who specializes in immigration questions to see whether there are other options. But PLEASE stay on the straight and narrow in all things related to work in the US. If you only have a tourist visa, you are not allowed to work.
I wish you all the best.