Give an Old Laptop New Life with Cheap (or Free) Projects:

http://lifehacker.com/359389/give-an-old-laptop-new-life-with-cheap-or-free-projectsx

Turn Your Old PC into a Webapp Monster with gOS. If you've got an extra PC gathering dust, gOS is not only a worthy operating system for a cheap PC from Wal-Mart; it's also an excellent (and free) way to repurpose your old PC.
 
http://lifehacker.com/software/hack-attack/turn-your-old-pc-into-a-webapp-monster-with-gos-318346.php

Email: Gmail
Chat: Meebo
News: Google News
Calendar: Google Calendar
Maps: Google Maps
Office: Google Docs and Spreadsheets
Shopping: Google Product Search
Social Networking: Facebook
Online Video: YouTube
Reference: Wikipedia
Blogging: Blogger

Turn Laptop to Digital Picture frame:
http://www.tacosntonic.com/pictures/Projects/Digital%20Picture%20Frame/
http://www.tacosntonic.com/2006/03/digital-picture-frame-from-an-old-laptop/