You want to copy audio CDs with Ubuntu and/or extract songs from an audio CD to files (MP3, Ogg Vorbis, ...) to listen to them with an MP3 player. With Ubuntu, that should be simple but not always ... howver with command line that works ! !
You want to fill in PDF forms on Ubuntu : here is a solution.
You want to share contacts and calendar between an Android phone and the emails reader Thunderbird (on a computer), here is a solution !
You want to modify PDF on Ubuntu : here is a solution.
You want to know the differences between similar files : here are some solutions !
You want to use subtitles with SUP format: here's how to do it !
You've forgotten the keyboard shortcut for Ubuntu 12.04 with Unity ?
Two lists that might be helpfull !
You want to burn mixed CD (aka Extra CD), i.e. with Audio tracks (so you can use them on HiFi equipments) and data tracks on Ubuntu or Lubuntu : here's your answer !
With Ubuntu, there are many ways to connect to a remote computer.