We'll be seeing rare spawns a little more commonly this weekend. Here's a note from EQLive:

Love is in the Air, causing hearts all over to grow larger and larger. Those rarely seen special denizens all across Norrath and beyond want to see adventurers more and more. From 10:00 am PST on Friday, February 12th until 11:59 PST Monday, February 15th, several rare encounters will increase the rate of their appearance.

Be sure to "show them how much you care about them" during this special time of year!