The documentation here contains a brief intro to using Sandboxed Solutions followed by a description of each solution in the project.

How to use Sandboxed Solutions

This project contains WSP files that you may download and use immediately in SharePoint 2010. These WSP files are designed to be deployed as "Sandboxed Solutions" by Site Collection Administrators.

SandBoxed Solutions are a new solution type in SharePoint 2010 that run in a safe environment that cannot destabilize the farm. In SharePoint 2010, you can add a new Sandboxed Solution to any site collection using the solution gallery for the site collection. The solution gallery is available at the root of the site collection by selecting Site Actions>>Site Settings>>Galleries>>Solutions. Using the Gallery, simply upload and activate the solution.

Sandboxed Solutions are severely restricted in functionality in order to prevent them from destabilizing the farm. However, a full-trust proxy may be created, which allows access to normally-restricted resources. This project contains
both sandboxed and full-trust proxy solutions. The full-trust proxies are deployed as Farm solutions and then called by a sandbox solution. If the solution requires a full-trust proxy, you will need appropriate rights to install that portion in the farm. Look for details on each solution.

Solution Documentation

This section contains documentation for each of the solutions available in the project in alphabetical order.

Detect Sandbox Web Part

A sample web part that detects whether it is running as a Sandboxed Solution or Farm Solution. This approach helps your solutions know what resources are available to them.

Print List

Print List adds a Print button to the Actions group of the ribbon for task, announcement, link, contact, and custom lists. It works using the JavaScript Client Object Model from a site page. The site page uses a custom master page to strip away the chrome and generate a printer-friendly view.
Requires Full-Trust Proxy: No

SharePoint Logger

The SharePoint Logger solution is a full-trust proxy that logs to the Unified Logging System (ULS) logs. It is useful for all of your sandboxed solutions because any of them can use it to log to the ULS system. The SharePoint Logger is a farm-level solution. Simply install it in Central Administration and make sure it is activated. When called, the SharePoint Logger will write to the log and returns a Guid, which is the CorrelationId so you can find the entry in the logs. A companion project named SharePointLoggerWebParts.wsp contains a simple web part that is deployed as a sandboxed solution and shows how to call the SharePoint Logger. Follow this pattern in all of your sandboxed solutions.
Requires Full-Trust Proxy: Yes

Sync to SharePoint Workspace

This is a set of two web parts. One web part lists all of the sites in the current collection. The other lists the SharePoint lists in the current site. Each item is presented as a hyperlink. When clicked, synchronization with the SharePoint Workspace is initiated. This allows users to sync multiple items from a single location.

Windows Links

Windows Links is a sandboxed solution that implements a Links list that can open links in new windows. Simply upload this to the Site Collection solution gallery and activate. The new list type will then be available for creation.
Requires Full-Trust Proxy: No