Create a useful alias that surves rebooting.
Change your prompt to be something cool and include at least two special codes.
Create an alias that named "howmany" that tells you how many people are logged in.
Have bash print the amount of free space on the disk.
Have bash reformat the hard drive every login.
Pick any four of the five above.


See http://www.gentoo.org/doc/en/articles/prompt-magic.xml

See http://www.ibiblio.org/pub/linux/docs/HOWTO/other-formats/html_single/Bash-Prompt-HOWTO.html
especially section 2.5 and 6.1