BeepBox

BeepBox is a browser-based tool for sketching instrumental music, and it is made by John Nesky. You add notes to patterns, layer instruments, and press play. The whole song is stored in the URL, which means you share your creation by simply sending a link,. That makes it a great way to write a 20-second chiptune and send it to a friend. It has a distinctive retro sound and a grid-style editor that feels more like a puzzle than a studio, which helps beginners get something going quickly. You can learn a lot by experimenting, and the results can be surprisingly good. It is best on a desktop, since the editor expects a mouse and a larger screen. Start with the default patterns, change a few notes, then copy the address when you are happy with it.