A selection of sites you can play with fonts:
FONT DE MUSIC - add music to your font
FONTSELF various fonts with embed codes
MYLIVESIGNATURE create your handwritten signature for e-mails and blog posts.
TEXTANIM animate your text
ICON SCRABBLE - use icons to make a text
SPELL WITH FLICKR Use Flickr images to create a text. (Contribution by Drew McAllister)