I just got this in my industry news email:

Celebrate Carnival's 35 Years of Fun with Sizzling Savings,
Free Upgrades, and Hot New Caribbean Itineraries during our
35 TH ANNIVERSARY
ONE DAY SALE
CARNIVAL'S BIGGEST EVER


How do you celebrate the 35th anniversary of the world's most popular cruise line? Easy, by giving the gifts of BIG savings and FREE upgrades to the guests who got us here.

THURSDAY ONLY
BIG savings and
FREE upgrades on:
3 & 4 Day
Cruises
from $249 *

5 Day
Cruises
from $299 *

7 Day
Cruises
from $499 *

Oceanview and Balcony staterooms available!

Book this Thursday, March 22nd and you'll receive FREE upgrades -- to the best available stateroom -- on any of our variety of hot new Caribbean itineraries and more.

Come celebrate 35 years in the Caribbean with Carnival.
Book your cruise Thursday.

Call Your Personal Vacation Planner or any travel agent.

and the fine print:
Cruise rates are in U.S. dollars, per person and are based on category 4A. Fare code must be requested to receive promotion. Offer combinable with Super Saver rates only. Government taxes and fees are additional for all guests. Full deposit required at the time of booking. Offer is non-transferable and has no cash value. Offer is capacity controlled and is not combinable with any other discount or promotional offer. Rates are subject to change at any time without prior notice. Upgrades available in categories 4A-8I. Excludes categories 1A/5A/7A/6E/9A/11/12/IS/OV/BL/ST. Best available stateroom upgrades available within like cabin categories (Interior to Interior, Oceanview to Oceanview and Balcony to Balcony). Oceanview upgrade NOT available on Carnival Spirit, Pride, Miracle or Legend. Excludes Europe sailings. Valid on new individual bookings made on March 21st & March 22nd, 2007 on select sailings thru 12/16/07. Other sail dates in range slightly higher. Blackout dates may apply. Some restrictions (including stateroom/category availability) apply. Credit for previous purchases is not permitted and guests who previously booked, cancelled and then rebooked during this period are not eligible. Request fare code CP1S. Ships' Registry: Panama & The Bahamas.