Random character

Get a random character to be used with a fancy/dingbats font as ornament

Using AppleScript (by Flip)

-- Save as script and call from GeekTool with "osascript path_to_the_script" 
set ls to "abcdefgh" -- characters to use (find them in TextEdit using the font you want then copy/paste)
set n to count items of ls
set theSeed to do shell script "head -n 1 /dev/random" 
set x to random number from 1 to n with seed theSeed
return (item x of ls)

Using shell

echo "\x@echo \"obase=16;$((25*$RANDOM/32767+97))\"|bc@"

Ok... mmm... This one may require some explanation :-)
This one returns a lowercase letter from a to z.
97 refers to the first ascii code you want (see man ascii)
25 is last ascii code - first ascii code (that is last ascii code - 97)

Using Perl* (by Brandon)

perl -e '@a=qw(a b c d e);print $a[rand($#a)]'

Twitter feeds

Friends timeline

curl --basic --user user:password http://twitter.com/statuses/friends_timeline.rss 2> /dev/null | grep title | sed 's/.*<title>//;s/<\/title>//' | perl -MHTML::Entities -ne 'binmode(STDOUT, ":utf8");print decode_entities($_)'

Search query

curl --basic http://search.twitter.com/search.atom?q=geektool 2> /dev/null | grep title | sed 's/.*<title>//;s/<\/title>//' | perl -MHTML::Entities -ne 'binmode(STDOUT, ":utf8");print decode_entities($_)'

Calendar

Simple Calendar

Change the LANG to suit your locale (get it in terminal by typing "echo $LANG")
export LANG=fr_FR;cal | sed "s/ $(date +%e) / $(echo  '\033[40m\033[1;31m')$(date +%e)$(echo  '\033[0m') /"
Alternatively, you can mark the current day this way (by Chris Ferrara) :
export LANG=fr_FR;cal | sed "s/^/ /;s/$/ /;s/ $(date +%e) / $(date +%e | sed 's/./#/g') /"