Membase (couchbase)

Use it to share cache between multiple applications (and servers) 
Download:

http://www.couchbase.com/download

http://blog.couchbase.com/membase-server-now-couchbase-server

Scott Hanselman's 2011 Ultimate Developer and Power Users Tool List for Windows

This list is just amazing
http://www.hanselman.com/blog/ScottHanselmans2011UltimateDeveloperAndPowerUsersToolListForWindows.aspx

Json.NET

The Json.NET library makes working with JavaScript and JSON formatted data in .NET simple...

http://james.newtonking.com/pages/json-net.aspx

CodePlex
Dowload

JSONLint / The JSON Validator

http://jsonlint.com/