smartphone
, fun
For me it is:
I can record a video with my son promising a thing and use it to enforce him to do that later.
Simple and I will never forget to bring it wherever I go.
It's like a dick Tracey watch. I can send video messages, watch youtube videos, surf the net, post on facebook/twitter, remote control my home computer, use the IR to change the channel on TVs, look up my location on a map, search for businesses on the map and get directions, look up resistor values, play Nintendo games, keep track of my car's MPG, I can go on.
When you are traveling alot, say for work. Take a picture of the lot where you parked your car. (With the Red B or Green 7 or whatever the landmark is). Take a picture of the entrance to the lot, so you remember how to get in.
Take pictures of the luggage stubs/tickets, whatever.
Because when you get back a week later, for the 6th time in 2 months, you will have no recollection where you left your car, or pretty much any specific detail that repeats!
(From a Hanselminutes podcast but still a great idea).
I can scan barcodes of food items and automatically track my nutrition for the day.
Edit
Here's the link to the app for android, Calorie Counter
I think it's use as a remote control for my computer is pretty cool (playing music with TunesRemote, controlling a video with VLC Remote, or moving the mouse and keyboard with GMote). Also, being able to find good restaurants/bars/gas stations while travelling in other cities has impressed a lot of my friends (using Yelp).
Um...
Here is my phone normally:
It does this:
Isn't that cool?!
One of the coolest things I've used it for was to identify objects in the night sky using Google Sky Map.
Some Android coolness...
How about exercise apps? Is exercising cool? I can use "My Tracks" or "Cardio Trainer" and track where I'm running, how fast, what my pace is, and time all with one app. And Cardio Trainer allows me to choose what type of workout it is so I can independently track different types of workouts.
Or for those WoW fans you can download the "Battle.Net Mobile Authenticator" which uses an algorithm to generate codes that when setup on your Battle.Net account, have to be entered to login. This gives you an extra layer of security protecting your account and achievements.
How about "Our Groceries" which is essentially a checklist app that can sync with any other mobile device and allows you to create lists and add items from the web.
For me its not one specific app rather the collection that make my iphone the perfect travel companion in one day with one small box I can
all with one charge cable
Detect metal.
If you've got an android with a compass, you can too: http://www.appbrain.com/app/com.imkurt.metaldetector
Here's a nice video of it in action: http://www.youtube.com/watch?v=WYu2cPRo3tQ
I've never done this myself since I use a different bank, but with Chase you can take pictures of your checks with the camera and with their app they will get deposited into your account.
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