Hi Wen! If you like brunch, dinner, wine tasting, drinks, films, museums, cooking parties, celebrity chef dinners, walking tours, make new friends, meet new people; then I cordially invite you to join my group: http://www.meetup.com/New-York-Dining...
As many of you know, there are several different Chinese meetup groups in New York. At most of these meetups, speakers of all levels are welcome. This means that quite a large percentage of the conversation tends to be in English.
To learn and improve, it's necessary to immerse oneself and not to feel as if you can just switch to English anytime you want. I have started this meetup to create a place where intermediate, advanced, or native speakers can go and speak entirely in Chinese. Sure, you can translate a word or explain something complicated in English if necessary, but other than that, we're keeping it entirely in Mandarin.
You should join this group and come to this meetup if you can have a basic conversation in Mandarin, if you have lived or traveled in a Chinese-speaking country for some length of time, if you have studied Chinese in school or on your own for a while, or if you are a native speaker. Basically, you should be able to speak Chinese to some extent already if you show up here. The whole goal is to keep the role of English as absolutely minimal as possible when we meet.
That being said, if you are intermediate, don't be intimidated. I myself am hardly fluent, but if you have the basics down and want to improve your vocabulary and natural speaking, the best way to do it is to force yourself to use what you know and expose yourself to things you don't!
If you're not sure whether it is right for you, just ask.