If you followed the instructions properly for Asset Pipeline, but your glyphicons won’t work, you might have set a variable wrong. It can help to comment out the following scss bootstrap variable definitions:

// $icon-font-path: if($bootstrap-sass-asset-helper, "bootstrap/", "../fonts/bootstrap/") !default;
//** File name for all font files.
// $icon-font-name:          "glyphicons-halflings-regular" !default;
//** Element ID within SVG icon file.
// $icon-font-svg-id:        "glyphicons_halflingsregular" !default;

also make sure to load bootstrap in the appropriate order in application.sass:

@import "bootstrap_vars"
@import "bootstrap-sprockets"
@import "bootstrap"