Ultra Runs 50K - 100K - 100 Miles
There are a few past and future races.
1)  In August 2008, I ran the Kat'cina Mosa 100K trail run.  This 62-mile race begins just a few miles from Provo Utah and climbs 17,404 feet over               the100K run.  That is more than three miles straight up.  Unfortunately I did not finish.  I did run 40 miles and climb13,700 ft.  More important, I    learned a lot about how to run a 100 mile race.  I was actually happy with my results.  Temperatures on the course reached100 degrees, I ran              out of water over an hour below the Windy Pass Aid Station on a stretch of trail with almost NO shade and several other errors.
2)  The Imogene Pass Run in Telluride, Colorado.  Always held on the first weekend after Labor Day.
3)  The Stump Jump:  One tough 50K run in Chattanooga, TN climbing up and down Signal Mountain and Suck Creek Mtn.  Early October.
4)  The Pinhoti 100 Trail Run:  November 8th, 2008
5)  Mountain Mist 50 K:  This is the toughest 50K run in Alabama.  After Pinhoti is definitely the toughest of all. January 24, 2009.
6)  Mount Mitchell Challenge: (Maybe - I will wait and see what the weather is like.  Mitchell (the highest point east of the Rockies) can be brutal     in May during the Assault on Mt Mitchell Bike ride.  (Including but not limited to Snow and Sleet)  February 22
7)  The Leadville 100.  This is a 100 MILE run that starts in Leadville Colorado (10,200 ft) in mid August, 2009.  The run climbs over Hope                 Pass at 12,600 ft and back down to the turnaround at Winfield Co.  Then you go back over the pass and return to Leadville.  The lowest point                on the course is 9,200 ft.   The route climbs about 16,000 total feet.
8) IRONMAN Florida:  If I do all that training for a 100 mile race I might as well throw in at least one Ironman.  That is a 2.4 mile swim, 112 mile
     bike segment and a marathon (26.2 miles).  That is a total of 140.6 miles - but you get to sit down for most of it!!  (and you probably don't climb              more than 200 feet over the entire bike and run course.  The swim is another story.  If each wave is from 2 to 3 ft, I figure I will gain at least     3,000 ft over the2.4 miles.  At the Gulf Coast Tri in May '08, I probably gained 5,000 ft during the 1.2 mile swim - it was a little rough!
      9)  Lookout Mountain 100K,  December 19th. The race starts at Lula Lake Land Preserve on the east side of Lookout Mtn.
    10) Hardrock100.com  2010 - I have an 18.1 % Chance of getting in and I am going to try.  July 9-11, 2010
     11) Wasatch Front 100 mile endurance run:  Yes, this one too.  September 11-12.  I will have about 1 in 5 chance at getting in this one too.
     12) Leadville Again!!!
The Zombie Runner in THE PLACE for ultra runner supplies and information:  Take a look.   Zombie Runner.com

       The How-to for ultra running is Kevin Sayer's ultrarunner.com.  You can find out everything you ever wanted to know about ultras - or did not want         to know.  Things like what to wear,  what to eat,  where to ...... (take your pick), during an ultra trail run, at this web site. Ultra runner.com

Kat'cina Mosa 100K trail run Course profile
The Hardrock 100 begins in Silverton Colorado, goes through Ouray, to Telluride, to Ophr and back to Silverton.  It is not only considered one the hardest runs in America but one of, in not the toughest on Earth.  No, I have no plans to enter, right now!  The website is http://www.run100s.com/HR/
The Leadville 100 profile
That is 100 miles and 16,000 feet of cumulative climbing.  This is probably Americas most famous Ultras.  Certainly not the hardest.  The Hardrock 100 (below) gets that distinction.
Hope Pass
Powerline Climb
May Queen
Aid Station
Box Creek/Halfmoon
Aid Station
Aid Station