The Agenda module allows you to display a list of upcoming events from Google Calendar as a block on your website.
The events are automatically downloaded and cached from the Calendar IDs specified in the Agenda administration page. Unlimited calendars can be added, and the colours for each calendar can be specified in the CSS file.
The output is fully themeable, and uses jQuery for dynamic effects such as rounded corners, and click-toggling extra information.
Note: If your dates are displaying a day off, you might be suffering the effects of Daylight Savings Time. Try installing and enabling the Date API and Date Timezone modules, then Daylight Saving Times are handled correctly.