First commit: this starts off on a pretty solid foot because we iterated on it a lot already.

src/components/rounded_toggle.js

@@ -0,0 +1,42 @@
+import React from 'react';
+import PureRenderMixin from 'react-pure-render/mixin';
+
+var RoundedToggle = React.createClass({
+  mixins: [PureRenderMixin],
+  propTypes: {
+    options: React.PropTypes.array.isRequired,
+    active: React.PropTypes.string.isRequired,
+    onChange: React.PropTypes.func.isRequired
+  },
+  render() {
+    let { options, active } = this.props;
+    return (<div className='rounded-toggle inline short'>
+      {options.map(option =>
+        <RoundedToggleOption
+          key={option}
+          option={option}
+          onClick={this.props.onChange}
+          className={'strong ' + (option === active ? 'active': '')} />)}
+    </div>);
+  }
+});
+
+var RoundedToggleOption = React.createClass({
+  mixins: [PureRenderMixin],
+  propTypes: {
+    option: React.PropTypes.string.isRequired,
+    className: React.PropTypes.string.isRequired,
+    onClick: React.PropTypes.func.isRequired
+  },
+  onClick() {
+    this.props.onClick(this.props.option);
+  },
+  render() {
+    let { className, option } = this.props;
+    return (<a
+      onClick={this.onClick}
+      className={className}>{option}</a>);
+  }
+});
+
+module.exports = RoundedToggle;