Anything you like for making appointments ?

Hello all,

I'm trying to have users make appointments by clicking on a basic
weekly view on a calendar ... and am afraid to reinvent to wheel...but
can't seem to find anything available yet...

I can find pretty decent google calendar integration such as
http://gcal4ruby.rubyforge.org/

I can also find calendar helpers for display such as
http://dmix.ca/2009/06/weeklybuilder-a-weekly-calendar-plugin-for-rails/
or http://github.com/topfunky/calendar_helper/tree/master

thanks for your help