When activated on your iPad, Siri can do more than most people know. If you have an iOS enabled car, you can even use it to give commands to play iTunes Radio and more. Here are some useful sample commands for using Siri, iPad's personal assistant:

Command App/Source
Call Charlie Facetime
Launch Notes App Launching
Tell Susie I'll be there at 2 p.m. Messages
Schedule a meeting for tomorrow at 9 a.m. Calendar
How do I get home from here? Maps
Who won the World Series? Sports
Tweet my location Twitter
Post the picture I just took to Facebook Facebook
Find movies playing in my area Web
Play "As Time Goes By" Music
Remind me to call my boss at 6 Reminders
Will it be sunny today? Weather
Email John about the meeting next Wednesday Mail
What is the price of Intel stock? Stocks
Wake me up tomorrow at 6 am Clock
What is my phone number? Contacts
Note a new idea for a novel Notes
Where can I find Alicia? Find My Friends
Define geriatric WolframAlpha, Bing, or Wikipedia
Play iTunes Radio Jazz channel iTunes Radio