How do I create a pie chart using Bokeh?

All I'd like to do is create a pie chart. The Bokeh documentation covers a number of sophisticated charts, including a donut chart, but it doesn't seem to cover pie chart.

Is there any example of this?

Ultimately, the chart will need to be to be embedded in a webpage, so I'll need to take advantage of Bokeh's html embed capabilities.

The answer below is very outdated. The Donut function was part of the old bokeh.charts API that was deprecated and removed long ago. For any modern version of Bokeh (e.g. 0.13 or newer) you can create a pie chart using the wedge glyphs, as follows:

from math import pi

import pandas as pd

from bokeh.io import output_file, show
from bokeh.palettes import Category20c
from bokeh.plotting import figure
from bokeh.transform import cumsum

x = { 'United States': 157, 'United Kingdom': 93, 'Japan': 89, 'China': 63,
    'Germany': 44, 'India': 42, 'Italy': 40, 'Australia': 35,
    'Brazil': 32, 'France': 31, 'Taiwan': 31, 'Spain': 29 }

data = pd.Series(x).reset_index(name='value').rename(columns={'index':'country'})
data['angle'] = data['value']/data['value'].sum() * 2*pi
data['color'] = Category20c[len(x)]

p = figure(height=350, title="Pie Chart", toolbar_location=None,
    tools="hover", tooltips="@country: @value")

p.wedge(x=0, y=1, radius=0.4,
    start_angle=cumsum('angle', include_zero=True), end_angle=cumsum('angle'),
    line_color="white", fill_color='color', legend_field='country', source=data)

show(p)

OUTDATED BELOW

An example for Bokeh 0.8.1 using the bokeh.plotting interface:

from bokeh.plotting import *
from numpy import pi

# define starts/ends for wedges from percentages of a circle
percents = [0, 0.3, 0.4, 0.6, 0.9, 1]
starts = [p*2*pi for p in percents[:-1]]
ends = [p*2*pi for p in percents[1:]]

# a color for each pie piece
colors = ["red", "green", "blue", "orange", "yellow"]

p = figure(x_range=(-1,1), y_range=(-1,1))

p.wedge(x=0, y=0, radius=1, start_angle=starts, end_angle=ends, color=colors)

# display/save everythin  
output_file("pie.html")
show(p)

Bokeh >0.9 will correctly compute the bounding area of all glyphs, not just "pointlike" marker glyphs, and explicitly setting the ranges like this will not be required.