I was absolutely fascinated by the richness of the Ubuntu repository. Following is a list of some cool things that I came across.

1. Alarm Clock
2. Gnome Dia - A wonderful diagram drawing tool.
3. texify - A tool to convert code into embeddable form in a tex file.
4. Login screen themes from art.gnome.org
5. ispell (filename) does a wonderful job for spelling checking.
6. sed 's/saurabh/gupta/g' file1 > temp creates a new file with name temp changing all occurrences of saurabh with gupta in the file file1.