Multiplayer Orchestra (https://www.multiplayer-orchestra.com/) is a web application that allows you to virtually collaborate with musicians from around the world in real-time. Here are some key features:

• Large instrument selection: Choose from over 400 instruments, including pianos, guitars, drums, and orchestral instruments.
• Real-time collaboration: Play music simultaneously with other users, creating a virtual orchestra.
• Public and private rooms: Join public rooms to jam with others or create private rooms with a password for specific collaborations.
• Contests: Participate in contests to win prizes like Amazon gift cards by recording solo performances.

It's important to note that the website seems to be in beta based on the version information listed (Beta 0.30).