The Connected Services Sandbox contest was launched by Microsoft and BT at the 3GSM conference in Barcelona and gives developers a chance to win $25,000 for creating a 2.0 mashup. According to Computer World
Usage scenarios can include a combination of e-mail, instant messaging and document collaboration with Web services, like Windows Live, Microsoft MapPoint, Amazon.com Inc., eBay Inc., Google Inc. and Yahoo Inc.
I also found a list of web services available to start creating your mashups, including a webservice for Live Search and Amazon etc. Check it out here: http://www.networkmashups.com/ShowAllServices.aspx
To register for the competition go here: http://www.networkmashups.com/signup.aspx