Last night I looked at the Clemson Track and Trail Club 
website and noticed a 5K in Greenville today.  I did my long run on Thursday so was going to do a 5K run today anyway, and I decided I wanted to do the race and see how much I have improved.  Actually, I haven't done a 5K running race by itself before, but the triathlons I've done have had 5K runs, and I've done those faster than I run in practice.
Sometime between when I tentatively made the decision and when I got up this morning I got mixed up about when the race started, plus I felt I needed to be there early because I had not preregistered.  So I ended up at the race site at 7:45 for a race that didn't start until 10.  I thought about walking the course but it was so cold I just sat in my car and wrote.  I did go out about 9:30 and run nearly a mile slowly to warm up and then stretched.  I also ate a bagel, which I usually can't eat, and then was impatient when the race started a little late.
I had done my warmup on the first half mile of the course, so I knew it was uphill and then down.  I started fairly far back but a few people passed me right away.  I tried to keep a pace where I was breathing fairly hard and go faster (though my level of effort was lower) on the downhills.  I kept looking for people ahead of me to catch up to and was usually able to do so, though the man with two large children in a jog stroller I could catch up with on the uphills but then he would pull ahead when it was flatter.  I did walk the one water station and drink some water, and the steep uphill right after it.
That was at two miles and there was a person there with a watch who said my time was 17 something (which I can't believe was accurate, as neither by perceived effort nor by my GPS did I slow down the last mile). I realized then I had a chance of breaking 30 minutes, which was my dream time (my more realistic goal was 34 minutes because my fastest 5K in training was at an 11:57 pace).  With about half a mile to go a volunteer said "it's all downhill from here," but that turned out not to be true.  I slowed down on the uphill but I pushed that last half mile breathing very hard.  I was foolishly a little disappointed when I saw my time was 30:24.  Then when I caught my breath I looked at my GPS and found it said a pace of under 10 minutes a mile, which was really what my dream time was (that extra .1 mile keeps throwing me).  I was so happy I had done it.
I don't think my GPS gave me very reliable readings but 30:24 for a 5K is a pace of 9:48.  Amazing.  Last September I was thrilled to achieve a pace of 12 minutes a mile in a 5K, albeit in a triathlon.  My previous personal best 5K time was 36:02--that's a 15 percent improvement in six months!  Last May, also in a triathlon, my 5K run time was 40:27.
Today was a small race with mostly young people and I was first in my age group because I was the only one in my age group.  I hung around for the awards and was happy to get a medal.  Actually it is the first medal I have received--the other races where I placed in my age group gave hats instead and I haven't done any races that gave finishers medals.
Update: The 
official times are up and I corrected the time above by a couple of seconds.  Overall I was 70th out of 83.  Turns out I was second in my age group--I can see looking at the official results there were other errors as well when they announced the age group awards.