Another month, another batch of 30 free Android apps courtesy of Amazon. Like the bookseller's last Appstore promotion, the "Summer Self-Improvement Bundle" features $100/£100's worth of complimentary apps, as long as you download them within the next two days (so don't leave it 'til the weekend, basically). On-theme apps include exercise, nutrition, sleep, budgeting and learning aids, while games such as Sonic & Sega All-Stars Racing and Carcassonne should provide a little entertainment. Other notable freebies include Kayak Pro for travel planning and management, and popular read-it-later app Instapaper. Remember, Amazon's Appstore is available to any Android device (some side-loading required), not that we're saying you could use a little self-improving. You're perfect just the way you are.