Microsoft is holding invite-only events for select Windows Insider members to attend Windows 10 Fan Celebrations around the world on Wednesday, July 29. One of them is in New York City and Microsoft's Xbox Live programming head Larry "Major Nelson" Hryb will be giving away 50 invites for people to attend that event.
The Major Nelson site has the details on how you could score an invite. Basically, you have to email Hryb directly with the subject line NYC by Monday, July 27 at 11:59 p.m. Eastern time. You have to be 21 years old or older and be in the New York City area on July 29 to be eligible. (Sorry, Microsoft is not flying anyone out or giving them a hotel room). The 50 people will be picked and emailed the time and specific location for the Windows 10 fan event on Tuesday afternoon. The good news is that the invite allows the person to bring a guest as well.
Source: Major Nelson