An effortless way to track attendance
Are you an educator? Roster app lets you keep track of your students' attendance. Whether you are a college professor, workshop facilitator or a guitar instructor, forget clumsy piles of paper since your Android-powered phone is already in your pocket. More information on http://www.flapsapps.com/roster-android/
All features are available in demo, but you cannot add more than one class.
Requirements: Android 1.6+.

Get organized now! Task List is an effective and intuitive ToDo list app.

Speed up phone;
Save battery;
Auto kill & widget;

Quick App Killer is a tool to kill running tasks for speeding up your phone, saving your battery life;

Best task/app killer on Android Market.

This Calendar Widget offers many sizes and shows as many events as possible.

Business productivity for smartphones and tablets - contacts, calendar, tasks and memos.

Paperdroid is an offline article reading Android app that integrates with the excellent service Read It Later and/or Google Reader.
Found an interesting but long article while surfing in a costly internet point? Skimming hastily through your feeds for worthy posts? Just save the page to Read It Later (via bookmarklet, the Firefox extension etc.) or star it in Google Reader and have Paperdroid automatically download it to your trusty Android phone for offline reading pleasure - later.

Measures time spent on each app. See which apps to uninstall because you're not using them!
The most accurate app usage tracker! Accurate to less than a second on Android 1.6 and up.

Quick App Installer
install external android apps on your mobile, you can search any folder by typing the folder location or just place your apk files in your scard root folder and easily install them on your phone

ANDLABS brings to you the most simple, intuitive and lightweight file manager for Android devices.

The AL File Manager helps you to access and manage all the files on your SD-card.

Data sharing simplified: use gestures like throw n' catch and dragging

Apn4Apps disables mobile data when the screen is off and enables it when the selected application starts to run on the foreground