We all use mobile phones predominantly for making / attending calls and sending / receiving messages. I have listed below some other uses also.

Alarms

We can keep wake up alarms. Most of the mobiles have option to set different time for weekdays and weekends. So if we set it once it will

wake us up for ever.

Reminders

We can keep reminders for doing important things like attending a meeting, going to hospital etc. Also we can store the birthdays and

anniversaries of our dearest ones in calendar and set reminder for that so that we won't miss / forget to wish them on the occasion

Email & Internet

Most of the mobile service providers are providing the internet facility in minimum cost. Nowadays mobile versions for many applications

are available like gmail, yahoo mail, icici bank, citibank etc. We can check our mails and browse the internet also.

Photos

Almost all mobiles come with a camera. Only the pixel size differs. We can take photos and videos using our mobile whenever we need it.

We don't have to worry about digital cameras. Also we can transfer the photos easily to computer using bluetooth or USB.

Music

We can store all our favourite songs into the memory card and hear it whenever we think. We can create different playlists according to our need.

Also we can hear music from FM radio stations.

Data sharing

Using bluetooth we can easily copy images, music etc from/to our friend's mobile phone.

Finance management

Lot of softwares are available for keeping track of our expenses. We can download them to our mobile and can track our daily expenses very easily.

Professional usage

Mobile versions of microsoft word, excel, powerpoint etc are available. We can copy our office documents to our mobile and read that while travelling

or at home.

Games

We can download different categories of games like adventure, puzzle, racing etc and  enjoy playing it in our mobile.

Maps

We can use the Maps feature available in mobiles to find out the route for the places we travel.

Data storage

We can store our important personal information in the mobile and protect it with a password so that it is accessed by only us.

Calculations

We can make use of the calculator for making simple calculations. Even scientific calculators  and curreny converters are also available.

Power source

We can use it as source of power in darkness. Some mobiles have the facility of using the camera lights as torch lights also.

Calendar

Almost all mobiles have the calendar for atleast next 10 years. It will be very useful if we get the list of holidays for the year in it also.

I don't know whether it is already available.

Utility Softwares

Many utility softwares related to health, beauty, travel etc are available. We can download that and use it.