Ideas

[rachelreveley]

Animated loader
slider using radios
slide out form
Circular stickers
horizontal heading ribbons
active styles on menus such as border colour change
rating stars
General animation maybe test compatibility with an existing framework

radio switch
http://codepen.io/GhostRider/pen/tHdqC

Rotated table headings
http://codepen.io/gcyrillus/pen/EvCHi

mobile menu
http://codepen.io/wesbos/pen/lEkhq

Color gradients on themes
http://codepen.io/ckcoyle/pen/gldyJ

http://www.sitepoint.com/beyond-bootstrap-foundation-frameworks-never-heard/