Extension Methods from Chris Meijers
Type-safe Include: a completely type-safe way to include nested objects in scenarios with DomainServices and RIA in, for example, Silverlight applications. Example: Include(x=>x.Parent) instead of Include("Parent"). A more detailed explanation can be found at http://www.chrismeijers.com/post/Type-safe-Include-for-RIA-DomainServices.aspx
Removes items from a list based on a condition you provide. I have a feeling this should exist already but I can't find it. You can get the same results using 'where' but this method operates on the collection itself.
Removes items from a collection based on the condition you provide. This is useful if a query gives you some duplicates that you can't seem to get rid of. Some Linq2Sql queries are an example of this. Use this method afterward to strip things you know are in the list multiple times
Gets the value of a databinded property-path from an object. The property can have the form "Product.Type.Group".
Filters a list based on a comma-separated list of allowed values. This is a lot more concise than using a number of 'or' clauses