OK, Google: valuable voice commands for Android

Before you start talking, a note: For a fully hands-free experience, you'll need to set up always-listening voice control, which will allow your phone to wake up and start listening anytime you say "OK, Google." To do that, open the Google app on your device, tap the menu icon in the upper-left corner and tap Settings. Next, tap Voice and then "OK Google" Detection. Follow the steps there to enable the system and train it to recognize your voice.
If you have an older device that doesn't support that option, you can still use the commands listed below; you'll just have to tap the microphone icon on your home screen first to start the listening process.

Device control and tools

Turn Wi-Fi on/off
Turn Bluetooth on/off
Turn my flashlight on/off
Turn airplane mode on/off
Turn up/down the volume
Dim/brighten the screen
Enable/disable [battery saver mode] (and other system features, such as mute)
Take a photo/selfie
Record a video
Set a timer for [10 minutes]
Open [Yelp] (or any app)
Open [computerworld.com] (or any website)
Metronome
Bubble level
Flip a coin
Roll a die
Start a run (requires a fitness app like Strava, Runkeeper, Runtastic or Endomondo)

Time, weather and current information

What time is it in [Paris]?
What time zone is [Phoenix] in?
When is the sunset tonight?
When's the sunrise in [London]?
Do I need an umbrella today?
Is it going to rain this weekend?
When is it going to rain next?
What's the weather in [Kalamazoo]?
Will I need a jacket tomorrow?
How hot is it gonna be on [Saturday]?
When's the next [Cubs] game?
What was the score of the [Cardinals] game last night?
Did the [Marlins] win their last game?
What's [Google] stock trading at today? (or just spell out a stock ticker symbol -- e.g., "G-O-O-G")

Location and navigation

How's the traffic to work?
Is [Steak 'n Shake] open right now?
How late is [Office Depot] open?
What time does [Target] open tomorrow?
What's a good [Mexican] place near me?
What's the best [sushi] nearby?
What restaurants are near me?
Where is the nearest [Burger King]?
Where's a [museum] around here?
Where's the closest [bowling alley]?
What movies are playing nearby?
Navigate to [123 South Main Street]
Go to [California Pizza Kitchen] with public transportation
Take me to [Bank of America] by foot
Take me home

Messaging and communication

Text [Grover] that [I'm running late]
Send text to [Ernie], mobile -- [I enjoy cheese]
Send email to [Gordon] -- [I'll call you in 20 minutes]
Send email to [Guy Smiley]. Subject: [Pickles.] Body: [Dill is always the way to go]
Send [Hangout] message to [Bert] -- [wanna grab lunch?] (also works with WhatsApp and other third-party messaging clients)
Start a video call with [Maria]
Post to Twitter -- [What a gorgeous day!] (requires Twitter app to be installed)
Post to Google+ -- [Hello, all of you stunning people] (requires Google+ app to be installed)
Check my voicemail
Read my messages
Call [Mom], mobile/home/work
Call [my brother] on speakerphone
Call [McDonald's on Third Street]
Call the [Hilton in Downtown Chicago]
What is [Zoe's] number?
What's the phone number for [Applebee's]?
What is area code [323]?

Organization and personal info

Add to my [grocery] list (or any list name you want -- your phone will prompt you to speak the item or items you want to add; when finished, say either "finished" or "that's it")
Add [Purchase beef] to my [to-do] list (or any list name you want; with this command as well as the previous command and the next two commands, you'll be able to choose to have the info saved into Google Keep or any other compatible note-taking app)
Note to self: [The Beef Purchasers would be a good name for a band]
Write this down for me: [There are different ways you can make a note to yourself by speaking]
Remind me to [take out the trash] in [two hours]
Remind me to [put out dog food] when [I get home]
Remind me to call [the boss] when [I'm at the airport]
Remind me to [eat at Canter's] next time [I'm in L.A.]
Wake me up at [7 a.m.] [tomorrow]
Set an appointment for a [haircut] [tomorrow at noon]
When is my next meeting/appointment?
What's my schedule for [July 17th]?
What does my day look like on [the 3rd]?
When is [Father's Day]?
When will my package arrive? (requires shipping confirmation to be present in Gmail)
Show me my bills (requires bills to be present in Gmail)
Show me my bills due this week/next week/[in July] (requires bills to be present in Gmail)
Show me my photos from [France] (requires photos to be present in Google Photos)

Music and video

Listen to [The Beatles]
Listen to ["No Rain"]
Listen to [party music]
Play music for [working out]
Listen to [Pearl Jam] on [Spotify]
Next song
Pause the music
Play me [Soundgarden] videos on YouTube
Show me the trailer for ["Ice Age 5"]
What's this song? (identifies music playing out loud in the room)

Travel

When does [United flight 1807] arrive?
Is [Southwest 2093] on time?
Is my flight on time? (requires confirmation to be present in Gmail)
Find me a nonstop flight from [L.A. to Chicago]
Show me my trip in [October] (requires confirmation to be present in Gmail)
Show me my trip to [Chicago] (requires confirmation to be present in Gmail)
Show me my hotel reservations (requires confirmation to be present in Gmail)
Where's my hotel? (requires confirmation to be present in Gmail)
Show me restaurants near my hotel (requires confirmation to be present in Gmail)
Search for hotels in [Boston]
Book me a table at [Plum Tree Inn] (requires OpenTable app to be installed)
Translate ["sausage"] to [German]
What's [French] for ["cheese"]?