Everyone should avoid e-cards or other "fun links" associated with Halloween. The Storm Worm has also been adapted to trick folks as noted by Websense. Clicking on these links could lead to hours of restoration and repair work. 
Storm Worm - New Halloween based attacks
http://www.websense.com/securitylabs/alerts/alert.php?AlertID=814
QUOTE: Websense® Security Labs™ has confirmed that the Storm worm has once again switched lure tactics. The worm has now adopted a Halloween twist in its attempts to infect users with malicious code. The first copies of the new emails began going out just before 9:00am PST on Tuesday, October 30th. As with previous Storm emails, various subjects and bodies will be used. Here is one example email:
Example of new Halloween based attacks
Subject: Nothing is funnier this Halloween
Body: Come watch the little skeleton dance.
(Malicious URL Removed)