W3Schools - literally everything I know about HTML and CSS, I've learned from here.
Dither it! - easy image dithering.
Photomosh - free JPG, GIF and WEBM editor, with watermark.
/home
"Currently listening to..." widget: From max's apartment, the exact verbatim code used on the page is avaliable here.
Current time widget: From this forum answer.
/music
Coutdown: From W3Schools.
"Last played" widget: Sadly I can't remember where I got it from, but here is the code