Looking for something different or to do just a swim / bike / or run?  
(pst - it's a great way to work on your weakness : )!

Swims
3 Mile Bridge Swim - Pensacola Florida, May
500 meter, 1.2 mile, 2.4 mile, 3.1 (5k) mile Bridge Swim - July, Iowa
Open Water Swim Venues in the UK!! Lots of cool ideas here ; )
5 K Big Shoulders - Lake Michigan, Chicago, September
Maui Channel Swim - Maui, August - done as a relay between 2 Hawaiian Islands ; ) woot!
2.4 mile Waikiki Roughwater Swim - Labour Day Weekend, Oahu, Hawaii

Bike
Triple By-Pass, Colorado - July
Ragbrai - Ride across Iowa - all about FUN!! - July
Pedalers Jamborie - Memorial Day Weekend, Katy Trail

Runs 

Triathlons
Burrito Union Triathlon - September, Superior, Wisconsin