Depends on the information you want to time track. In one company we had just to track our total working times a day (tax/social insurance purpose). The easieast solution was:
last. More granular you could just do something like
echo -e -n `date`\tProjectName\tTask\tComment >> MyTimeTable.txt
...whatever...
echo -e \t`date` >> MyTimeTable.txt
and procsessing with the usual suspects (grep, awk, ...).
When you need even more functionality, I dont know anyone which works without a gui.
