Create Digital Music has an article about WebSID, a web-based Commodore 64 synthesizer that you can play with in Chrome for iOS!
Yes, WebSID is a beautifully-grungy emulation of the legendary SID synthesis in the Commodore 64. Because it runs in a Web browser, it’s also stupidly-simple to use. On computers, the keys are cleverly mapped to your keyboard, so you can jam by typing. On a phone or tablet with capable browser, you can use touch, meaning this is a bit like having an app.
It sounds remarkable, all using the Web Audio API, with a nice filter, envelope controls, and delay, plus lots of authentic sound features (including properly arpeggiating polyphonic chords). It’s good enough that I might just jam on the thing and record. If you do the same, send it our way.
This is the reason news has been delayed today, I've been having a lot of fun with this! You can find it here. Open up that filter and send a lot of feedback into the delay for a great gritty chip sound.
You can play polyphonicly, but there are some occasional bugs and it does bog down when you manipulate the controls. Even on an iPad Air the controls seemed a bit sluggish, but I was just impressed that I could tweak them while playing notes simultaneously! Good free fun for the weekend!