I actually didn't know about a couple of these which is why I wanted to share... They did an awesome job so I just kept it in its original format. All credit to How-To Geek for this. I'm posting this in the S3 section, but it applies to just about any device running Jelly Bean with Google Now.
via How-To Geek
16 Android Voice Actions to Make Android Your Own Personal Assistant
Android may not have Siri, but it does have Voice Actions. Voice Actions are a powerful way to perform actions – searching, getting directions, making notes, setting alarms, and more – with just your voice.
Google’s voice recognition has become surprisingly good, but – like all voice recognition – it isn’t perfect. Be sure to enunciate clearly whenever you’re speaking to a computer.
Performing Voice Actions
To start a voice action, either tap the microphone icon on the Google search widget at the top of your home screen or open Google Now and say “Google” out loud.
Your phone or tablet will start listening to your voice. You can now say something out loud to perform a voice action.
Perform a Google Search
The most basic – and obvious – of voice actions is as a simple Google Search. If you say something that Google doesn’t recognize as another voice action, it will perform a simple Google search for it. If you say something like “photos of narwhals”, Google will perform a search for narwhal photos and show them to you.
However, this feature also works hand-in-hand with Google’s new knowledge graph. If you search for something Google knows the answer to – like “How many people live on Earth?” – Google will show you the answer to your question and speak it back to you. This feature will only get more powerful as Google’s knowledge graph improves.
Open an App
You can say “Open [app]” to open an app. For example, “Open Gmail” opens the Gmail app.
Set an Alarm
To quickly set an alarm, say “Set alarm for [time]”. You can say something like “Set alarm for 20 minutes from now” or “Set alarm for 7 a.m.”.
You can also add a label. For example, you could say “Set alarm for 30 minutes from now, label, laundry is done.”
Make a Note
To make a note to yourself, say “note to self” and continue talking to leave your note.
This creates a note – both in audio and transcribed text – that will be emailed to your Gmail account. It’s fine if the transcription isn’t perfect, as you can play back the audio later.
Create a Calendar Event
You can easily create a calendar event by speaking it. For example, you could say “Create a calendar event: Business Lunch in New York, Friday at noon.”
Send an Email
Voice Actions can be used to send an entire email. For example, you could say “Send email to Bob Smith, subject, Our meeting, message, I’ll be right there.”
Send a Text Message
Voice actions can send text messages in the same way it can send emails. For example, you could instead say “Send SMS to Bob Smith, message, I’m on my way.”
Make a Phone Call
To make a phone call, say “Call” followed by a phone number, a contact’s name, or a business.
Scan a Barcode
You don’t need a separate barcode-scanner app on your phone. Whenever you want to scan a barcode or QR code, say “Scan a barcode” and Google will give you a barcode-scanner.
Identify a Song
You don’t need a song-identification app like Shazam installed, either. Whenever you want to identify a specific song, ask “What’s this song?” and Google will give you a song-identification widget that uses your device’s microphone to identify a currently playing song.
(This only seems to work in countries with Google Music.)
Listen to a Song
You can easily start listening to a song with voice actions. Just say “listen to” followed by the name of a song, artist, or album. You’ll be able to choose an app, such as Play Music or YouTube.
Go to a Website
You can open a specific website by saying “Go to [website address]”. For example, “Go to How-To Geek dot com” would bring you to our website.
View a Map
To view a map of an address or city, say “map of [location]”. For example, you could say “map of Vancouver” or “map of 123 fake street, New York”
To get directions to a location, say “directions to [location]”. This opens the Google Maps app with directions to your specified location.
To start getting turn-by-turn navigation directions to a location, say “navigate to [location]”. This opens the Google Navigation app and starts navigating.
Post to Google+
If you use Google+, you can use Voice Actions to post directly to it. Just say “Post to Google+” followed by your message.
You can also perform a voice action just by typing it into the Google search box. For example, typing “scan a barcode” into the Google search widget on Android and tapping the search key will bring up the barcode scanner.
Image Credit: Dru Kelly on Flickr