Could use help modeling something

From: Jamie Jackson (junxies_at_hotmail.com)
Date: 03/23/04 

Date: Mon, 22 Mar 2004 22:47:16 -0500

At the heart of an event registration system (people registering to
attend a conference, training, etc.), I've got three classes...

Event---Registration---Registrant

...where a registrant signs up to attend an event. The sticky
requirement is that from Event to Event, different Registration will
be collected. Likewise, depending on the event, different Registrant
details might be collected.

I don't know how to model these Event-dependent
Registrant/Registration details. At first glance, I'd think I'd need
Event-specific subclasses for Registration and Registrant, but I don't
know how... I'm just too fuzzy on this stuff still.

Tips would be appreciated. (Keep in mind I'm an OO beginner.)

Thanks,
Jamie